Rotary damper
By incorporating gaps with controlled linear expansion coefficients, the rotary damper addresses the issue of increased operating time at low temperatures, ensuring consistent performance through controlled fluid flow.
Patent Information
- Application Number
- JP2023100147
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-06-19
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2043-06-19
AI Technical Summary
Existing rotary dampers experience a significant increase in operating time at low temperatures due to the contraction of the valve, which blocks the movement of viscous fluid, leading to a high rate of change in operating time.
The design incorporates a first gap between the end wall and a protrusion with a larger linear expansion coefficient than the vane, and a second gap equal to or larger than the first gap when the valve contracts, allowing viscous fluid to flow freely, reducing the impact of temperature changes.
This configuration minimizes the rate of change in operating time at low temperatures by ensuring the viscous fluid can move without obstruction, maintaining efficient operation across temperature variations.
Smart Images
Figure 2025000342000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a rotary damper. [Background technology]
[0002] For example, Japanese Patent No. 5918222 discloses a rotary damper comprising a valve having a linear expansion coefficient greater than that of the vane, the valve having a fluid chamber into which a viscous fluid is injected, a vane installed in the fluid chamber, an end wall closing one end of the fluid chamber, a seal portion installed between the peripheral wall of the fluid chamber and the vane, and a protrusion protruding from the seal portion and installed between the vane and the end wall, the protrusion being supported by a support portion formed on the vane when the valve is closed (see Example 2 of the same publication).
[0003] In this rotary damper, the axial length of the vane is set shorter than the length between the end wall (second end wall) closing the other end of the fluid chamber so that the vane does not contact the end wall (second end wall) (see Example 2 of the same publication). However, since the linear expansion coefficient of the vane is smaller than that of the valve, the axial length of the vane at low temperature (for example, ambient temperature is -30 degrees Celsius) hardly changes compared to that at normal temperature (for example, ambient temperature is +25 degrees Celsius). On the other hand, since the linear expansion coefficient of the valve is larger than that of the vane, the axial length of the valve changes more than the vane at low temperature. Therefore, even if the valve contracts at low temperature and the gap between the end wall and the protruding portion expands, the movement of the viscous fluid is blocked by the support portion. As a result, there was a problem in that the rate of change of the operating time at low temperature (((operating time at low temperature)-(operating time at normal temperature)) / (operating time at normal temperature)×100) was high. The operating time is the time required for the rotor to rotate a given angle when a given rotational force is applied. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Patent No. 5918222 Summary of the Invention [Problem to be solved by the invention]
[0005] The problem to be solved by the present invention is to reduce the rate of change in operating time at low temperatures. [Means for solving the problem]
[0006] In order to solve the above problems, the present invention provides a fluid chamber into which the viscous fluid is injected; A vane disposed in the fluid chamber; A first end wall that closes one end of the fluid chamber; and a valve having a seal portion disposed between a peripheral wall of the fluid chamber and the vane, and a first protruding portion protruding from the seal portion and disposed between the vane and the first end wall, the valve having a linear expansion coefficient greater than a linear expansion coefficient of the vane; When the valve is closed, a first gap is formed between the first end wall and the first protrusion, a second gap is formed between the first end wall and a first support portion formed on the vane, and the first protrusion is supported by the first support portion, The second gap is set to be equal to or larger than the first gap when the valve contracts due to a decrease in temperature. A rotary damper is provided. Effect of the Invention
[0007] According to the present invention, when the valve is closed, the first gap is formed between the first end wall and the first protrusion, and the viscous fluid moves through the first gap. In addition, since the valve has a linear expansion coefficient larger than that of the vane, when the temperature drops from room temperature, the first protrusion contracts to increase the first gap. Furthermore, since the second gap between the first end wall and the first support is set to be equal to or larger than the first gap when the valve contracts due to a drop in temperature, the movement of the viscous fluid is not blocked by the first support. Therefore, it is possible to reduce the rate of change in operating time at low temperatures. [Brief description of the drawings]
[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view of a rotary damper according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the rotary damper according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view of the rotor employed in the first embodiment. [Figure 4] FIG. 4 is a perspective view of the valve employed in the first embodiment. [Diagram 5] FIG. 5 is an assembly diagram of the rotor and valve. [Figure 6] FIG. 6 shows the valve in an open state. [Figure 7] FIG. 7 is a diagram showing the valve in a closed state. [Figure 8] FIG. 8 is a schematic diagram showing the first gap. [Figure 9] FIG. 9 is a schematic diagram showing the second gap. [Figure 10] FIG. 10 is a vertical sectional view of the rotary damper according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. EXAMPLES
[0010] 1 and 2, the rotary damper according to the first embodiment includes a housing 10, a rotor 20, and a valve 30. The housing 10 and the rotor 20 are made of a metal such as a zinc alloy, and the valve 30 is made of a resin such as polyoxymethylene. Therefore, the linear expansion coefficient of the valve 30 is larger than the linear expansion coefficient of the vane 22 constituting the rotor 20.
[0011] The housing 10 includes a cylindrical peripheral wall 10a, a partition wall 10b protruding from the peripheral wall 10a, a bottom wall 10c closing one end of the peripheral wall 10a, and a lid 10d closing the other end of the peripheral wall 10a. The partition wall 10b is a partition that separates two fluid chambers 40 formed in the housing 10.
[0012] The fluid chamber 40 is a space into which a liquid viscous fluid such as oil is injected, and is formed around the shaft 20a that constitutes the rotor 20. The fluid chamber 40 is divided into two chambers, a first chamber 40a and a second chamber 40b, by the vane 20b and the valve 30 that constitute the rotor 20.
[0013] The rotor 20 is configured to have a shaft 20a and vanes 20b protruding from the shaft 20a. The shaft 20a is connected to an object that transmits a rotational force to the rotor 20. However, depending on the mode of use, there may be cases where the housing 10 rotates around the rotor 20. In this case, the shaft 20a is connected to an object that prevents the rotor 20 from rotating.
[0014] In the first embodiment, one end of the shaft 20a is supported by a protrusion 10e formed on the housing 10. In this configuration, when a valve, which will be described later, is closed, a viscous fluid flows between the shaft 20a and the protrusion 10e, and the shaft 20a floats toward the lid 10d that constitutes the housing 10. Therefore, in the first embodiment, the bottom wall 10c that constitutes the housing 10 corresponds to the "first end wall that closes one end of the fluid chamber" of the present invention.
[0015] The vane 20b is disposed in the fluid chamber 40 and moves within the fluid chamber 40 as the shaft 20a rotates.
[0016] 3, the vane 20b used in the embodiment includes a first pressurizing portion 20c for pressurizing the viscous fluid in the first chamber 40a and a second pressurizing portion 20d for pressurizing the viscous fluid in the second chamber 40b. The first pressurizing portion 20c and the second pressurizing portion 20d are provided at a fixed interval.
[0017] 4, the valve 30 employed in the embodiment is configured to have a seal portion 30a, a first protruding portion 30b, a second protruding portion 30c, and a third protruding portion 30d. The seal portion 30a has a width that allows it to always contact the tip surface of the first pressurizing portion 20c and the tip surface of the second pressurizing portion 20d, and is installed between the peripheral wall 10a of the fluid chamber 40 (the peripheral wall 10a constituting the housing 10) and the vane 20b (the first pressurizing portion 20c and the second pressurizing portion 20d). The first protruding portion 30b protrudes from the seal portion 30a and is installed between the vane 20b (the second pressurizing portion 20d) and the first end wall 10c of the fluid chamber 40 (the bottom wall 10c constituting the housing 10). The second protruding portion 30c protrudes from the seal portion 30a and is installed between the vane 20b (the second pressurizing portion 20d) and the second end wall 10d of the fluid chamber 40 (the lid 10d constituting the housing 10). The third protruding portion 30d protrudes from the seal portion 30a and is disposed between the first pressure portion 20c and the second pressure portion 20d.
[0018] The seal portion 30a is formed with a first flow passage 50a communicating with the first chamber 40a and a second flow passage 50b communicating with the second chamber 40b. A third flow passage 50c is formed on the tip surface of the third protruding portion 30d, and a fourth flow passage 50d communicating between the first flow passage 50a and the third flow passage 50c is formed on the side surface of the third protruding portion 30d.
[0019] 3 and 5, the vane 20b (first pressurizing portion 20c) is formed with a first support portion 20e that supports the first protruding portion 30b when the valve 30 is closed. The first support portion 20e is a portion of the first pressurizing portion 20c that can come into contact with the first protruding portion 30b, and serves to prevent damage to the valve 30 by reducing the load applied to the boundary portion between the first protruding portion 30b and the seal portion 30a when the valve 30 is closed. In addition, the vane 20b (first pressurizing portion 20c) is formed with a second support portion 20f that supports the second protruding portion 30c when the valve 30 is closed. The second support portion 20f is a portion of the first pressurizing portion 20c that can come into contact with the second protruding portion 30c, and serves to prevent damage to the valve 30 by reducing the load applied to the boundary portion between the second protruding portion 30c and the seal portion 30a when the valve 30 is closed.
[0020] 6, when the rotor 20 rotates in one direction (counterclockwise in FIG. 2), the seal portion 30a of the valve 30 receives pressure from the viscous fluid, causing the third protrusion portion 30d to come into contact with the second pressurizing portion 20d, and all of the first flow path 50a, the second flow path 50b, the third flow path 50c, and the fourth flow path 50d are opened. In this manner, when the valve 30 is in an open state, the viscous fluid in the first chamber 40a pressurized by the first pressurizing portion 20c passes through the first gap G1 and the second gap G2 described below, as well as the first flow path 50a, the third flow path 50c, the fourth flow path 50d, and the second flow path 50b in this order to move to the second chamber 40b, so that no braking force that slows down the rotational speed of the rotor 20 is generated.
[0021] 7, when the rotor 20 rotates in the reverse direction (clockwise direction in FIG. 2), the seal portion 30a of the valve 30 receives the pressure of the viscous fluid, causing the third protrusion portion 30d to come into contact with the first pressurizing portion 20c, and the first flow path 50a and the third flow path 50c are closed. In this manner, when the valve 30 is in a closed state, the viscous fluid in the second chamber 40b pressurized by the second pressurizing portion 20d cannot move to the first chamber 40a through the third flow path 50c and the first flow path 50a. Therefore, the viscous fluid in the second chamber 40b moves to the first chamber 40a through the first gap G1 and the second gap G2 described later, generating a braking force that decelerates the rotational speed of the rotor 20.
[0022] 8, when the valve 30 is closed, a first gap G1 is formed between the first end wall 10c (the bottom wall 10c constituting the housing 10) of the fluid chamber 40 and the first protrusion 30b constituting the valve 30. In this embodiment, the dimension D1 of the first gap G1 at room temperature (ambient temperature +25 degrees Celsius) is set to about 0.2 mm.
[0023] 9, when the valve 30 is closed, the second gap G2 is formed between the first end wall 10c (the bottom wall 10c constituting the housing 10) of the fluid chamber 40 and the first support portion 20e formed on the vane 20b. In the embodiment, the dimension D2 of the second gap G2 at room temperature (ambient temperature +25 degrees Celsius) is set to about 0.3 mm. Note that in FIG. 9, the valve 30 is omitted for ease of understanding.
[0024] At low temperatures (ambient temperature is -30 degrees Celsius), the first protrusion 30b shrinks more than at normal temperature, so the dimension D1 of the first gap G1 becomes approximately 0.3 mm. Meanwhile, the dimension D2 of the second gap G2 is approximately the same at low temperatures as at normal temperature. As the ambient temperature becomes lower, the viscosity of the viscous fluid increases, but the first gap G1 becomes larger, and the dimension D2 (approximately 0.3 mm) of the second gap G2 is the same as the dimension D1 (approximately 0.3 mm) of the first gap G1. As a result, the first support portion 20e does not block the movement of the viscous fluid, so the rate of change in operating time at low temperatures can be reduced.
[0025] The effect was confirmed by comparing Example 1 with the comparative example. In the comparative example, the dimension D1 of the first gap G1 at room temperature was set to about 0.2 mm, similar to Example 1. The dimension D2 of the second gap G2 at room temperature in the comparative example was set to about 0.2 mm, different from Example 1. The operating time was measured as the time required for the rotor rotated at 40 Newton meters to rotate 60°. The change rate of the operating time at low temperature in Example 1 (((operating time at low temperature)-(operating time at room temperature)) / (operating time at room temperature)×100) was about 65%. On the other hand, the change rate of the operating time at low temperature in the comparative example was about 188%. In Example 1, the change rate of the operating time at low temperature could be reduced by about 123% compared to the comparative example.
[0026] In order to prevent the first support portion 20e from blocking the movement of the viscous fluid, it is preferable that the second gap G2 be set to be the same as or larger than the first gap G1 when the valve 30 contracts due to a decrease in temperature.
[0027] The second protrusion 30c stabilizes the position of the vane 20b in the axial direction when the valve 30 is closed. That is, in the first embodiment, since the second protrusion 30c is interposed between the vane 20b and the second end wall 10d (the lid 10d constituting the housing 10) of the fluid chamber 40, the axial movement of the vane 20b is suppressed even if the shaft 20a tries to float toward the lid 10d when the valve 30 is closed. This makes it easier to control the dimensions of the first gap G1 and the second gap G2 according to the ambient temperature.
[0028] Unlike the first embodiment, in the configuration in which the shaft 20a floats in the direction of the bottom wall 10c constituting the housing 10 when the valve 30 is closed, the "lid 10d" of the first embodiment corresponds to the "first end wall" of the present invention, the "second protruding portion 30c" of the first embodiment corresponds to the "first protruding portion" of the present invention, the "second support portion 20f" of the first embodiment corresponds to the "first support portion" of the present invention, the "first gap" of the present invention is formed between the "lid 10d" and the "second protruding portion 30c" of the first embodiment, and the "second gap" of the present invention is formed between the "lid 10d" and the "second support portion 20f" of the first embodiment. Also, the "bottom wall 10c" of the first embodiment corresponds to the "second end wall" of the present invention, the "first protruding portion 30b" of the first embodiment corresponds to the "second protruding portion" of the present invention, and the "first support portion 20e" of the first embodiment corresponds to the "second support portion" of the present invention. EXAMPLES
[0029] 10, the rotary damper according to the second embodiment has a configuration in which the rotor 20 may not move in the axial direction. That is, one end of the rotor 20 is inserted into a first through hole 10f formed in the bottom wall 10c of the housing 10, and the other end of the rotor 20 is inserted into a second through hole 10g formed in the lid 10d of the housing 10. The rotor 20 and the valve 30 employed in the second embodiment are the same as those employed in the first embodiment.
[0030] In such a configuration, when the rotor rotates with a gap between the first protrusion 30b of the valve 30 and the bottom wall 10c of the housing 10 and between the second protrusion 30c of the valve 30 and the lid 10d of the housing 10, when the valve 30 is closed, a first gap G1 is formed between the first end wall 10c (the bottom wall 10c of the housing 10) and the first protrusion 30b, a second gap G2 is formed between the first end wall 10c and the first support portion 20e, and the first protrusion 30b is supported by the first support portion 20e, a third gap (not shown) is formed between the second end wall 10d (the lid 10d of the housing 10) and the second protrusion 30c, a fourth gap (not shown) is formed between the second end wall 10d and the second support portion 20f, and the second protrusion 30c is supported by the second support portion 20f. The second gap G2 is set to be equal to or larger than the first gap G1 when the valve 30 contracts due to a drop in temperature, and the fourth gap is set to be equal to or larger than the third gap when the valve 30 contracts due to a drop in temperature.
[0031] According to this configuration, when the valve 30 is closed, the first gap G1 and the third gap are formed, so that the viscous fluid moves through the first gap G1 and the third gap. In addition, since the valve 30 has a linear expansion coefficient larger than that of the vane 20b, when the temperature drops from room temperature, the first protruding portion 30b contracts to increase the first gap G1, and the second protruding portion 30c contracts to increase the third gap. Furthermore, since the second gap G2 is set to be equal to or larger than the first gap G1 when the valve 30 contracts due to a drop in temperature, and the fourth gap is set to be equal to or larger than the third gap when the valve 30 contracts due to a drop in temperature, the movement of the viscous fluid is not blocked by the first support portion 20e and the second support portion 20f. Therefore, similar to the first embodiment, the rate of change in the operating time at low temperatures can be reduced. [Explanation of symbols]
[0032] 10. Housing 10a Peripheral wall 10b Bulkhead 10c Bottom wall (1st end wall) 10d Cover (second end wall) 10e Convex part 10f 1st through hole 10g 2nd through hole 20 rotors 20a shaft 20b Vane 20c First pressure section 20d Second pressure section 20e 1st support part 20f 2nd support part 30 Valve 30a Seal part 30b 1st protrusion 30c 2nd protrusion 30d 3rd protrusion 40 Fluid chamber 40a Room 1 40b Room 2 50a First flow path 50b Second flow path 50c Third flow path G1 First gap G2 Second gap
Claims
1. a fluid chamber into which the viscous fluid is injected; A vane disposed in the fluid chamber; A first end wall closing one end of the fluid chamber; and a valve having a seal portion disposed between a peripheral wall of the fluid chamber and the vane, and a first protruding portion protruding from the seal portion and disposed between the vane and the first end wall, the valve having a linear expansion coefficient greater than a linear expansion coefficient of the vane; When the valve is closed, a first gap is formed between the first end wall and the first protrusion, a second gap is formed between the first end wall and a first support portion formed on the vane, and the first protrusion is supported by the first support portion, A rotary damper in which the second gap is set to be equal to or larger than the first gap when the valve contracts due to a decrease in temperature.
2. a second end wall that closes the other end of the fluid chamber; the valve has a second projection projecting from the seal portion and disposed between the vane and the second end wall; 2. The rotary damper according to claim 1, wherein the second protrusion stabilizes a position of the vane in the axial direction when the valve is closed, and is supported by a second support portion formed on the vane.
3. a second end wall that closes the other end of the fluid chamber; the valve has a second projection projecting from the seal portion and disposed between the vane and the second end wall; When the valve is closed, a third gap is formed between the second end wall and the second protruding portion, a fourth gap is formed between the second end wall and a second support portion formed on the vane, and the second protruding portion is supported by the second support portion, 2. The rotary damper according to claim 1, wherein the fourth gap is set to be equal to or larger than the third gap when the valve contracts due to a decrease in temperature.
Citation Information
Patent Citations
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