Seat vibration isolation structure and design method thereof

Abstract

The invention relates to the field of seats, in particular to a seat vibration isolation structure and a design method thereof.The seat vibration isolation structure comprises an outer framework, and a rubber framework is arranged in the outer framework; the external framework is connected with a seat, and the rubber framework is connected with a vehicle body; the rubber framework protrudes out of the outer framework; by using the external framework and the rubber framework, rigid connection between a traditional seat and a vehicle body is avoided; the riding comfort of the seat is improved; meanwhile, the rubber framework is required to have enough different vertical and lateral static rigidities, so that enough vibration transmission attenuation can be ensured, and meanwhile, the static rigidity of a seat mounting point can be ensured. While vertical excitation of a road surface, a power assembly and a suspension transmitted to a seat through a vehicle body is guaranteed to be attenuated, enough rigidity can be provided in the lateral direction, and lateral vibration of the seat is avoided.

Description

Technical Field

[0001] The invention relates to the field of seats, in particular to a seat vibration isolation structure and a design method thereof. Background Art

[0002] Car seats support the bodies of drivers and passengers, reduce vibrations caused by car bumps, and relieve travel fatigue. Car seats are one of the most critical components affecting driving comfort.

[0003] The car seat is rigidly connected to the body floor by bolts. When the vehicle is driving, the excitation of the road surface, powertrain and suspension will be transmitted to the seat through the body floor, causing the seat to vibrate and affecting the driving experience.

[0004] Traditional seats have poor vibration reduction effects, and some existing high-end vibration reduction measures bring expensive costs and cannot be popularized in some low-end commuter vehicles.

[0005] Some car seat cushioning devices currently on the market, such as the adjustable car seat shock absorber disclosed in patent (CN201268250Y), include an upper base plate, a lower base plate and a support frame. The support frame is balanced between the upper and lower base plates by two groups of cross brackets connected in the middle, and a shock-absorbing support arm is provided in the middle of the two groups of cross brackets.

[0006] The seat shock absorber can effectively absorb the vibration of the vehicle and improve the comfort. The overall structure of the seat is relatively complex and cannot effectively reduce the vibration transmitted from the vehicle body to the seat.

[0007] Therefore, in order to improve or solve at least one problem, it is necessary to optimize the design of the existing seat or seat connection structure. Summary of the invention

[0008] The object of the present invention is to provide a seat vibration isolation structure which can be used for connecting a seat to a vehicle body and can also play a vibration reduction role.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A seat vibration isolation structure comprises an external frame, wherein a rubber frame is arranged inside the external frame; the external frame is connected to the seat, and the rubber frame is connected to the vehicle body; the rubber frame protrudes from the external frame.

[0011] The external frame is a metal frame.

[0012] The external frame includes a frame sleeve, a fastening mechanism is provided on the outer side of the frame sleeve, the fastening mechanism includes a support seat, and the support seat is provided with a seat fastening hole; the rubber frame includes a rubber body, and the rubber body is inserted into the frame sleeve;

[0013] The rubber body is provided with a vehicle body fastening hole.

[0014] The rubber body is arranged close to a protruding frame sleeve on one side of the vehicle body.

[0015] The fastening mechanism comprises a plurality of support seats, and the plurality of support seats are evenly distributed on the outside of the skeleton sleeve at intervals; each support seat is distributed in the middle area of ​​the skeleton sleeve.

[0016] A design method for the seat vibration isolation structure, the design method comprising the following steps:

[0017] Step 1: Decouple the suspension and seat frequencies; the natural frequency of the suspension is required to be different from the natural frequency of the seat;

[0018] Step 2: When the seat is not equipped with a seat vibration isolation structure, collect the actual vibration amplitude and corresponding frequency of the seat;

[0019] And obtain and record the actual vertical displacement of each seat installation point of the seat when the vehicle is running;

[0020] Step 3: Under the actual displacement recorded in step 2, obtain the required vertical static stiffness of the rubber skeleton;

[0021] Step 4: After step 3 is completed, it is required that the difference between the natural frequency of the seat back when the seat vibration isolation structure is installed and the natural frequency of the seat back when the seat vibration isolation structure is not installed is not greater than 1.0 Hz; and then the lateral static stiffness of the rubber skeleton is obtained;

[0022] Step 5: Based on the vertical static stiffness obtained in step 3 and the lateral static stiffness obtained in step 4, design a rubber frame and seat vibration isolation structure that meets the requirements.

[0023] In the step 1, it is required that the deviation between the natural frequency of the suspension and the natural frequency of the seat is at least 4.0 Hz.

[0024] In step 3, it is required that after the vibration is transmitted by the seat vibration isolation structure, the vibration attenuation is not less than 20 dB.

[0025] In the step 2, it is required to arrange the position sensor at the seat mounting point to obtain the actual vertical displacement of the corresponding seat mounting point.

[0026] After the seat vibration isolation structure design is completed, install the seat vibration isolation structure on the vehicle;

[0027] Then, a vibration sensor is arranged on the nut of the connecting bolt when the rubber frame is connected to the car body; another vibration sensor is arranged on the nut of the connecting bolt when the external frame is connected to the seat; then the vehicle runs normally, and the vibration values ​​collected by the two vibration sensors are compared. If the difference between the vibration values ​​collected by the two vibration sensors is not less than 20dB, it means that the vertical stiffness of the seat vibration isolation structure meets the requirements. Otherwise, it means that the vertical stiffness of the seat vibration isolation structure does not meet the requirements.

[0028] The advantages of the present invention are:

[0029] The invention discloses a seat vibration isolation structure and a design method thereof.

[0030] The present invention avoids the rigid connection between the traditional seat and the vehicle body by using the external frame and the rubber frame, thereby increasing the comfort of the seat.

[0031] At the same time, the present invention requires that the rubber skeleton has sufficient vertical and lateral static stiffness differences, so as to ensure sufficient vibration transmission attenuation while ensuring the static stiffness of the seat mounting point. While ensuring the attenuation of the vertical excitation transmitted to the seat through the vehicle body by the road surface, powertrain and suspension, it can also provide sufficient lateral rigidity to avoid lateral vibration of the seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0033] Figure 1 It is a top view of the seat vibration isolation structure of the present invention.

[0034] Figure 2 It is a cross-sectional view of the seat vibration isolation structure of the present invention.

[0035] Figure 3 It is a schematic diagram of the structure when the present invention is connected with the vehicle body and the seat.

[0036] The marks in the above figure are:

[0037] 1. External frame, 2. Support seat, 3. Rubber frame, 4. Body, 5. Seat. DETAILED DESCRIPTION

[0038] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0039] A seat vibration isolation structure includes an external frame 1, wherein a rubber frame 3 is arranged inside the external frame 1; the external frame 1 is connected to a seat 5, and the rubber frame 3 is connected to a vehicle body 4; the rubber frame 3 protrudes from the external frame 1; the present invention avoids the rigid connection between the traditional seat 5 and the vehicle body 4 by using the external frame 1 and the rubber frame 3, thereby increasing the riding comfort of the seat 5.

[0040] At the same time, the present invention requires that the rubber skeleton 3 has sufficient vertical and lateral static stiffness differences, so as to ensure sufficient vibration transmission attenuation while ensuring the static stiffness of the seat 5 installation point. While ensuring the attenuation of the vertical excitation transmitted to the seat 5 through the vehicle body 4 by the road surface, powertrain and suspension, it can also provide sufficient lateral rigidity to avoid lateral vibration of the seat 5.

[0041] The seat vibration isolation structure of the present invention is mainly arranged at the connection position between the seat 5 and the vehicle body 4. The traditional seat 5 bracket is connected to the vehicle body 4. The basic function of the seat vibration isolation structure of the present invention is to act as a connecting piece. The seat 5 can be fixed to the vehicle body 4 through the seat vibration isolation structure; in the present invention, the seat 5 generally has four installation points with the vehicle body 4, so the seat 5 is generally connected to the vehicle body 4 through four seat vibration isolation structures.

[0042] In the present invention, the seat vibration isolation structure mainly includes an external frame 1, and a rubber frame 3 is arranged inside the external frame 1; the external frame 1 is connected to the seat 5, and the rubber frame 3 is connected to the vehicle body 4; the rubber frame 3 is inside the external frame 1, and the external frame 1 ensures the structural strength of the seat vibration isolation structure, and the rubber frame 3 mainly plays the role of subsequent vibration isolation and vibration reduction.

[0043] In the present invention, the external skeleton 1 and the rubber skeleton 3 can be connected by a vulcanization process.

[0044] In the present invention, the rubber skeleton 3 is arranged to protrude from the external skeleton 1; based on such an arrangement, it is possible to avoid the external skeleton 1 colliding with the vehicle body 4 and generating abnormal noise during subsequent use.

[0045] In the present invention, the external frame 1 is a metal frame; the metal frame can ensure the structural strength of the external frame 1, and a steel sleeve or an alloy sleeve can be selected, and the specific selection can be made according to needs.

[0046] Furthermore, the external skeleton 1 in the present invention includes a skeleton sleeve 11, which is mainly a cylindrical tube column structure. A fastening mechanism is provided on the outer side surface of the skeleton sleeve 11 in the present invention. The setting of the fastening mechanism facilitates the connection between the external skeleton 1 and the seat 5.

[0047] In the present invention, the fastening mechanism comprises a support base 2 , on which a seat fastening hole 21 is provided; the subsequent seat 5 is connected to the support base 2 by bolts.

[0048] In the present invention, the rubber skeleton 3 includes a rubber body, which is inserted into the skeleton sleeve 11; the rubber body is provided with a vehicle body fastening hole 31; when used later, the rubber skeleton 3 is connected to the vehicle body 4 by bolts.

[0049] At the same time, in the present invention, the protruding frame sleeve 11 is arranged on the side of the rubber body close to the vehicle body 4; such an arrangement can prevent the external frame 1 from hitting the vehicle body 4 and generating abnormal noise during subsequent use.

[0050] Furthermore, the fastening mechanism in the present invention includes a plurality of support seats 2, and the plurality of support seats 2 are evenly spaced and distributed on the outside of the skeleton sleeve 11; based on the above design, it is convenient for the skeleton sleeve 11 and the seat 5 to have multiple connection points, thereby extremely ensuring the stability of the connection between the seat 5 and the seat vibration isolation structure.

[0051] In addition, in the present invention, each support seat 2 is distributed in the middle area of ​​the skeleton sleeve 11; this arrangement forms a step platform at the connection between the support seat 2 and the skeleton sleeve 11. During subsequent use, the skeleton sleeve 11 can be plugged into the seat 5, thereby better ensuring the stability and accuracy of the connection between the seat 5 and the seat vibration isolation structure.

[0052] A design method for the seat vibration isolation structure, the design method comprising the following steps:

[0053] Step 1: Decouple the frequency of the suspension and the seat 5; the natural frequency of the suspension is required to be different from the natural frequency of the seat 5;

[0054] Step 2: When the seat 5 is not equipped with a seat vibration isolation structure, the actual vibration amplitude and the corresponding frequency of the seat 5 are collected;

[0055] And obtain the actual vertical displacement of each seat 5 installation point when the vehicle is running; and record it;

[0056] Step 3: Under the actual displacement recorded in step 2, obtain the required vertical static stiffness of the rubber skeleton 3;

[0057] Step 4: After step 3 is completed, it is required that the difference between the natural frequency of the seat 5 backrest when the seat vibration isolation structure is installed and the natural frequency of the seat 5 backrest when the seat vibration isolation structure is not installed is not greater than 1.0 Hz; and then the lateral static stiffness of the rubber skeleton 3 is obtained;

[0058] Step 5: Based on the vertical static stiffness obtained in step 3 and the lateral static stiffness obtained in step 4, a rubber frame 3 and a seat vibration isolation structure that meet the requirements are designed.

[0059] Based on the above design, the seat vibration isolation structure design can be realized, ensuring that the seat vibration isolation structure meets the design requirements.

[0060] Furthermore, in step 1 described in the present invention, it is required that the deviation value between the natural frequency of the suspension and the natural frequency of the seat 5 is at least 4.0 Hz; based on such design requirements, the frequency decoupling of the suspension and the seat 5 can be achieved to avoid vibration amplification caused by resonance between the suspension and the seat 5; specifically, in the present invention, the natural frequencies of the suspension and the seat 5 are identified, and the structure of the seat 5 is adjusted so that the frequencies of the two are kept away from being above 4.0 Hz.

[0061] Furthermore, in step 3 of the present invention, it is required that the vibration attenuation is not less than 20 dB after the vibration is transmitted by the seat vibration isolation structure; based on such a setting, the vibration isolation and buffering of the seat 5 can be better achieved.

[0062] Furthermore, in step 2 described in the present invention, it is required to arrange the position sensor at the seat 5 mounting point to obtain the actual vertical displacement of the corresponding seat 5 mounting point; based on such a setting, it is convenient to detect the actual displacement of each seat 5 mounting point on the seat 5 under actual working conditions.

[0063] Furthermore, in the present invention, after the design of the seat vibration isolation structure is completed, the seat vibration isolation structure is installed on the whole vehicle; then a vibration sensor is arranged on the nut of the connecting bolt when the rubber frame 3 is connected to the vehicle body 4; another vibration sensor is arranged on the nut of the connecting bolt when the external frame 1 is connected to the seat 5; then the vehicle runs normally, and the vibration values ​​collected by the two vibration sensors are compared. If the difference between the vibration values ​​collected by the two vibration sensors is not less than 20dB, it means that the vertical stiffness of the seat vibration isolation structure meets the requirements, otherwise, it means that the vertical stiffness of the seat vibration isolation structure does not meet the requirements; through the above-mentioned operation arrangement, the vibration attenuation of the seat vibration isolation structure can be detected, which is used to detect whether the vertical static stiffness of the rubber frame 3 meets the design requirements; it plays a good verification role.

[0064] specific:

[0065] The present invention discloses a seat vibration isolation structure, which mainly comprises an external frame 1, wherein a rubber frame 3 is arranged inside the external frame 1; the external frame 1 is connected to a seat 5, and the rubber frame 3 is connected to a vehicle body 4; and the rubber frame 3 protrudes from the external frame 1.

[0066] The seat vibration isolation structure of the present invention is composed of a composite of metal and rubber materials, and is installed between the seat 5 and the vehicle body 4. The vertical and lateral (X, Y, and Z translational degrees of freedom in the vehicle coordinate system) static stiffness are different. The vertical direction mainly plays the role of attenuating vibration transmission, and the lateral direction plays the role of ensuring the static stiffness of the seat 5 installation point.

[0067] The metal part of the seat vibration isolation structure is connected to the seat 5, and the rubber frame 3 is connected to the vehicle body 4, which reduces the vertical vibration transmitted from the vehicle body 4 to the seat 5 while ensuring the static stiffness of the lateral mounting point of the seat 5, ensuring that the lateral modal reduction of the seat 5 is ≤1.0Hz, and ensuring that the seat 5 does not generate additional vibration.

[0068] Matching method: Based on the excitation frequency and amplitude characteristics of the actual vehicle dynamics, the control index is decomposed into the seat vibration isolation structure to solve the problem in a targeted manner and effectively reduce the vibration of the seat 5.

[0069] Specifically, in the present invention, the external frame 1 of the seat vibration isolation structure is a metal structure with a mounting point, which is connected to the seat 5 by bolts. The mounting point is mainly a support seat 2. A rubber frame 3 is provided inside the external frame 1. The rubber frame 3 is connected to the external frame 1 through a vulcanization process. A metal sleeve can be embedded in the middle of the rubber frame 3 and connected to the vehicle body 4 by bolts.

[0070] Method for matching seat vibration isolation structure performance with seat 5 performance:

[0071] 2.1 Frequency decoupling: identifying the natural frequencies of the suspension and seat 5, and adjusting the structure of the seat 5 to keep the frequencies of the two frequencies away from 4.0 Hz to avoid vibration amplification due to resonance;

[0072] 2.2 On the basis of meeting 2.1, collect the amplitude and frequency characteristics of the actual vibration of the seat 5 of the whole vehicle, obtain the actual displacement of the 54 installation points of the seat under the condition of driving at a constant speed of 50kph-120kph on rough roads, and record them. (50kph-120kph is a common working condition, and the vibration of the seat 5 is more obvious on rough roads. Other working conditions of concern can be customized);

[0073] Adjust the rubber skeleton 3 and its static stiffness to meet the following requirements under different degrees of freedom:

[0074] (1) Make its vertical static stiffness in the linear segment within the displacement range collected in 2.2 and have an attenuation of ≥20.0dB.

[0075] (2) Make its lateral static stiffness not less than 2000N / mm, and ensure that the lateral mode of the seat backrest 5 is reduced by ≤1.0Hz compared with that in 2.1.

[0076] 1. Based on 1.1 and 1.2, select appropriate mounting bolts according to the position and size of the mounting bracket of the seat 5 and the mounting point of the vehicle body 4 to achieve the matching of the seat 5, the seat vibration isolation structure and the vehicle body 4;

[0077] 2. Carry out modal frequency acquisition and propose decoupling requirements:

[0078] 2.1 Identify the natural modal frequencies of the suspension system and seat 5 under the vehicle boundary. The suspension mode is obtained through the conventional operating modal method, and the operating conditions are performed in accordance with the requirements of 2.2; the seat 5 modal frequency measurement point is defined as the excitation point and the response point are both on the upper part of the seat 5 backrest (close to the shoulder position of the passenger), and the test method adopts the conventional hammer modal test method. Record the first vertical natural frequency of the suspension and the first modal frequency of the seat 5 in the X and Y directions (using the vehicle coordinate system).

[0079] 2.2 Define the first lateral mode of seat 5 to be higher than the suspension mode by ≥4.0Hz; define the frequency difference between the X and Y frequencies of seat 5 to be ≥2Hz to avoid resonance amplification caused by the coupling of the suspension and seat 5 modal frequencies. If it is found that it does not meet the requirements, the seat 5 modal adjustment can be made by strengthening or weakening the seat 5 external frame 1.

[0080] 3. Determine the static stiffness of the rubber skeleton 3 in different degrees of freedom.

[0081] 3.1 Method for determining the static stiffness of the rubber frame 3 in the vertical direction (Z direction of the vehicle coordinate system):

[0082] The vibration of the tire, suspension and powertrain is mainly transmitted to the seat 5 in the normal direction (i.e. vertical direction) of the floor of the vehicle body 4. Therefore, the vertical vibration excitation is the most important excitation received by the seat 5. The vibration isolation effect is best when the rubber skeleton 3 is installed in this direction. Therefore, the definition method of the rubber vertical static stiffness is as follows:

[0083] 3.1.1 Obtain the vertical displacement at the installation points of the seat 5 of the actual vehicle: On the basis of meeting the decoupling requirements in 2.1, displacement sensors are arranged at the four installation points of the seat 5. The test conditions are performed in accordance with 2.1 of the invention content section to obtain the actual vertical displacement of the 54 installation points of the seat when the vehicle is driving on a rough road at a uniform speed of 50kph-120kph, and record the range from the maximum displacement to the minimum displacement.

[0084] 3.1.2 Under the displacement conditions recorded in 3.1.1, the vertical static stiffness 2 of the rubber skeleton 3 is required to be in the linear segment, and the vibration attenuation of the active and passive sides of the rubber skeleton 3 is required to be ≥ 20dB. The evaluation method is to arrange vibration sensors on the active and passive sides respectively, and the whole vehicle is operated according to the working condition 1 in 3.1.1, and the vibration values ​​are collected for comparison. The definition of the active and passive sides is shown in the figure below: In the present invention, the nut of the bolt connecting the rubber skeleton 3 and the vehicle body 4 is defined as the active side; the nut of the bolt connecting the seat 5 and the external frame 1 of the seat vibration isolation structure is defined as the passive side.

[0085] 3.1.3 Record the structure and static stiffness of the rubber under the conditions of 3.1.2.

[0086] 3.2 Definition method of static stiffness of rubber skeleton 3 lateral direction (X and Y translational freedom in vehicle coordinate system):

[0087] The backrest of seat 5 is a cantilever beam structure, which is more prone to lateral vibration. Therefore, in addition to meeting the requirements in 3.1.2, the backrest modal of seat 5 is required to be as high as possible, which is more conducive to suppressing vibration.

[0088] The static stiffness of the seat 5 mounting point is positively correlated with the seat 5 backrest mode. Therefore, the rubber frame 3 should be adjusted and matched to make its lateral static stiffness not less than 2000N / mm, and ensure that the lateral mode of the seat 5 backrest is reduced by ≤1.0Hz compared with that collected in 2.1, and record the rubber lateral static stiffness that meets the requirements.

[0089] 3.3 Record the rubber seat vibration isolation structure that simultaneously meets the static stiffness and vibration isolation requirements in the three degrees of freedom directions in 2.1 and 2.2, which is the physical structure required by the present invention, among which the realization process of static stiffness, modal frequency and vibration isolation is the matching method described in the present invention.

[0090] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A seat vibration isolation structure, characterized in that: It comprises an external frame, wherein a rubber frame is arranged inside the external frame; the external frame is connected with a seat, and the rubber frame is connected with a vehicle body; and the rubber frame protrudes from the external frame.

2. A seat vibration isolation structure according to claim 1, characterized in that: The external frame is a metal frame.

3. A seat vibration isolation structure according to claim 1, characterized in that: The external frame includes a frame sleeve, a fastening mechanism is provided on the outer side of the frame sleeve, the fastening mechanism includes a support seat, and the support seat is provided with a seat fastening hole; the rubber frame includes a rubber body, and the rubber body is inserted into the frame sleeve; The rubber body is provided with a vehicle body fastening hole.

4. A seat vibration isolation structure according to claim 3, characterized in that: The rubber body is arranged close to a protruding frame sleeve on one side of the vehicle body.

5. The seat vibration isolation structure according to claim 3, characterized in that: The fastening mechanism comprises a plurality of support seats, and the plurality of support seats are evenly distributed on the outside of the skeleton sleeve at intervals; each support seat is distributed in the middle area of ​​the skeleton sleeve.

6. A method for designing a seat vibration isolation structure according to any one of claims 1 to 5, characterized in that: The design method comprises the following steps: Step 1: Decouple the suspension and seat frequencies; the natural frequency of the suspension is required to be different from the natural frequency of the seat; Step 2: When the seat is not equipped with a seat vibration isolation structure, collect the actual vibration amplitude and corresponding frequency of the seat; And obtain the actual vertical displacement of each seat installation point of the seat when the vehicle is running; and record it; Step 3: Under the actual displacement recorded in step 2, obtain the required vertical static stiffness of the rubber skeleton; Step 4: After step 3 is completed, it is required that the difference between the natural frequency of the seat back when the seat vibration isolation structure is installed and the natural frequency of the seat back when the seat vibration isolation structure is not installed is not greater than 1.0 Hz; and then the lateral static stiffness of the rubber skeleton is obtained; Step 5: Based on the vertical static stiffness obtained in step 3 and the lateral static stiffness obtained in step 4, design a rubber frame and seat vibration isolation structure that meets the requirements.

7. The design method of the seat vibration isolation structure according to claim 6, characterized in that: In the step 1, it is required that the deviation between the natural frequency of the suspension and the natural frequency of the seat is at least 4.0 Hz.

8. The design method of the seat vibration isolation structure according to claim 6, characterized in that: In step 3, it is required that after the vibration is transmitted by the seat vibration isolation structure, the vibration attenuation is not less than 20 dB.

9. The design method of the seat vibration isolation structure according to claim 6, characterized in that: In the step 2, it is required to arrange the position sensor at the seat mounting point to obtain the actual vertical displacement of the corresponding seat mounting point.

10. The design method of the seat vibration isolation structure according to claim 9, characterized in that: After the seat vibration isolation structure design is completed, install the seat vibration isolation structure on the vehicle; Then, a vibration sensor is arranged on the nut of the connecting bolt when the rubber frame is connected to the car body; another vibration sensor is arranged on the nut of the connecting bolt when the external frame is connected to the seat; then the vehicle runs normally, and the vibration values ​​collected by the two vibration sensors are compared. If the difference between the vibration values ​​collected by the two vibration sensors is not less than 20dB, it means that the vertical stiffness of the seat vibration isolation structure meets the requirements. Otherwise, it means that the vertical stiffness of the seat vibration isolation structure does not meet the requirements.

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