Pedal feeling simulation device, electronic hydraulic braking system and automobile

Abstract

The utility model discloses a pedal feeling simulation device, an electronic hydraulic braking system and an automobile. The pedal feeling simulation device comprises a shell which is provided with an open end and a closed end and defines a simulator cavity; the piston is arranged in the simulator cavity, a hydraulic cavity is defined by the piston and the closed end, a pressure medium from the brake master cylinder can be supplied to the hydraulic cavity, and the pressure medium can generate pressure and act on the piston to push the piston to move; the lining is arranged on the side, away from the hydraulic cavity, of the piston in the simulator cavity; the metal spring is arranged between the open end and the lining; and the flexible medium is arranged between the lining and the metal spring, and the lining and the metal spring clamp the flexible medium. By the adoption of the technical scheme, noise, vibration and roughness caused by direct contact and collision of the lining and the metal spring are prevented. The problem that the step change of the pedal feeling is obvious when the lining is in direct contact with the metal spring is solved, so that the pedal feeling is smooth and continuous force feedback and is gradually changed instead of sudden step change.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of automobile, in particular to a pedal feeling simulation device, electronic hydraulic brake system and automobile. BACKGROUND

[0002] The existing pedal feeling simulation devices are mainly passive pedal simulator and active pedal simulator. The active pedal simulator takes the pedal stroke sensor signal as input, controls the motor rotation through the electronic control unit, thereby controls the building pressure performance of the simulator in real time, and simulates any pedal feeling. The active pedal simulator has high cost.

[0003] The passive pedal simulator usually relies on physical components such as springs and bushings to simulate the feeling of the pedal. They do not depend on complex electronic control units or sensors, so their structure and operation are relatively simple. In the passive pedal simulator, the feeling of the pedal is realized by the combination of these physical components.

[0004] The existing passive pedal simulator includes two kinds. One is to adopt the mode of elastomer and bushing. The passive pedal simulator has certain damping effect, but the performance of the elastomer will be significantly affected when the temperature changes greatly. Especially at low temperature, the hardness of the elastomer will increase. This makes the passive pedal simulator have different pedal feeling in different regions or seasons. And the elastomer needs a mold for production, and the cost is relatively high. The other is to adopt the mode of spring and bushing. Although the pedal feeling of the passive pedal simulator will not be affected by the temperature, but the step change of the pedal feeling when the spring and the bushing contact is obvious and the NVH problem is prominent. Among them, the step change of the pedal feeling when the spring and the bushing contact is obvious refers to that the transition of the pedal feeling is not smooth, but presents obvious stage change. NVH is the abbreviation of noise, vibration and harshness, which refers to the unpleasant sound, body feeling and other comfort-related factors that passengers feel during vehicle operation. SUMMARY

[0005] The utility model provides a pedal feeling simulation device for solving the above problems.

[0006] In a first aspect, the embodiments of the utility model discloses a pedal feeling simulation device, include: casing, have open end and closed end, casing defines simulator cavity, piston, be located in simulator cavity, piston and closed end define hydraulic chamber, the pressure medium from brake master cylinder can be supplied to hydraulic chamber, pressure medium can generate pressure and act on the piston to push the piston movement, bushing, be located in simulator cavity in the side of piston away from hydraulic chamber, metal spring, be located between open end and bushing, flexible medium, be located between bushing and metal spring, bushing and metal spring hold flexible medium.

[0007] Adopt above technical scheme, set up flexible medium between bushing and metal spring these two rigid components and buffer, prevent the noise, vibration and roughness caused by direct contact, collision of bushing and metal spring, wherein, roughness refers to the tactility experience that user feels when operating pedal feeling simulation device, not smooth or not smooth. In addition, through above technical scheme, still improved the problem that the step change of pedal feeling is obvious when bushing and metal spring directly contact, make that pedal feeling is smooth and continuous force feedback, is gradually changed, instead of sudden step change. This pedal feeling is real, delicate and simulates the feeling of the pedal in the real vehicle.

[0008] Optionally, the piston is cylindrical, including bottom wall and the circumferential wall extending from the bottom wall to the open end in the axial direction, the bushing includes a head portion and a main body portion, the main body portion is axially slidable on the radially inner side of the circumferential wall of the piston, and the head portion is in abutment with the flexible medium, and the pedal feeling simulation device further comprises a compression spring arranged between the main body portion of the bushing and the bottom wall of the piston.

[0009] Optionally, the flexible medium is cylindrical or circular truncated conical, and the two ends of the flexible medium in the axial direction are in abutment with the bushing and the metal spring respectively.

[0010] Optionally, the side of the head portion of the bushing in abutment with the flexible medium is planar, or the side of the head portion of the bushing in abutment with the flexible medium is provided with a central protrusion, and the side of the flexible medium in abutment with the head portion of the bushing is planar.

[0011] Optionally, the side of the flexible medium in abutment with the metal spring is planar, or the side of the flexible medium in abutment with the metal spring is provided with a central recess.

[0012] Optionally, the maximum outer diameter of the flexible medium is equal to the inner diameter of the casing.

[0013] Optionally, the pedal feeling simulation device comprises an end cover attached to the open end, and the metal spring is fixedly connected to the end cover.

[0014] In a second aspect, embodiments of the utility model disclose an electronic hydraulic brake system, including brake master cylinder, pressure providing device that can be electrically controlled and pressure modulation device for adjusting brake pressure at each wheel, and like in any preceding embodiment of the first aspect pedal feeling simulation device, pedal feeling simulation device is in fluid communication with brake master cylinder through hydraulic pipeline.

[0015] Optionally, the hydraulic pipeline is provided with an electrically-operated, normally-closed simulator valve.

[0016] In a third aspect, embodiments of the utility model disclose an automobile, including an electronic hydraulic brake system as in any preceding embodiment of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Show the three-dimensional of pedal feeling simulation device in the utility model embodiment Figure 1 ;

[0018] Figure 2 Show the three-dimensional of pedal feeling simulation device in the utility model embodiment Figure 2 ;

[0019] Figure 3 Show the cross section of pedal feeling simulation device in the utility model embodiment Figure 1 ;

[0020] Figure 4 Show the cross section of pedal feeling simulation device in the utility model embodiment Figure 2 ;

[0021] Figure 5 Show the side view of bushing in the utility model embodiment;

[0022] Figure 6 Show the side view of metal spring in the utility model embodiment;

[0023] Figure 7 Show the local schematic diagram of one example of electronic hydraulic brake system suitable for pedal feeling simulation device in the utility model embodiment. DETAILED DESCRIPTION

[0024] The following description of the embodiments will be better understood when read in conjunction with the accompanying drawings as follows. Although the description will be made below in conjunction with the preferred embodiments, it is not learned that the features of the present application are limited to the embodiments. On the contrary, the purpose of describing the present application in conjunction with the embodiments is to cover other alternatives or modifications based on the claims of the present application. In order to provide a better understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusion or obscure the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that in this specification, similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0026] The terms "first", "second", and the like are only used to distinguish description, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the embodiments, it should be noted that unless otherwise explicitly specified and limited, the terms "set", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments can be understood according to the specific circumstances.

[0028] In order to make the purpose, technical scheme and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0029] In the first aspect, with reference to Figures 1 to 4 The embodiments of the present application disclose a pedal feeling simulation device 10. The pedal feeling simulation device 10 comprises a housing 11, a piston 13, a bushing 14, a metal spring 16 and a flexible medium 19.

[0030] With reference to Figure 3 And Figure 4 The housing 11 has an open end 111 and a closed end 112. In the present embodiment, the housing 11 is substantially cylindrical. The housing 11 defines a simulator cavity 17. As Figure 3 And Figure 4As shown, the simulator cavity 17 is stepped. The simulator cavity 17 extends in the axial direction, i.e. the Z direction shown in the figure. The direction from the closed end 112 to the open end 111 is the first direction, i.e. the Z1 direction shown in the figure; the direction from the open end 111 to the closed end 112 is the second direction, i.e. the Z2 direction shown in the figure.

[0031] The piston 13 is arranged in the simulator cavity 17, and the piston 13 and the closed end 112 define a hydraulic chamber (not shown in the figure). Pressure medium from the brake master cylinder can be supplied to the hydraulic chamber, and the pressure medium can generate pressure and act on the piston 13 to push the piston 13 to move. The piston 13 moves in the axial direction, i.e. the Z direction shown in the figure.

[0032] The bushing 14 is arranged in the simulator cavity 17 on the side of the piston 13 away from the hydraulic chamber. The bushing 14 is made of metal. The metal spring 16 is arranged between the open end 111 and the bushing 14.

[0033] The flexible medium 19 is arranged between the bushing 14 and the metal spring 16. The bushing 14 and the metal spring 16 clamp the flexible medium 19. In this embodiment, the flexible medium 19 is fixedly connected to the metal spring 16.

[0034] In this embodiment, with reference to Figures 1 to 4 , along the direction from the closed end 112 to the open end 111, i.e. the first direction Z1, the simulator cavity 17 is provided with the piston 13, the bushing 14, the flexible medium 19, and the metal spring 16. The housing 11, the piston 13, the bushing 14, the flexible medium 19, and the metal spring 16 are coaxially arranged.

[0035] In this embodiment, pressure medium from the brake master cylinder can be supplied to the hydraulic chamber, and the pressure medium can generate pressure and act on the piston 13 to push the piston 13 to move in the first direction, i.e. the Z1 direction shown in the figure. After the piston 13 contacts the bushing 14, the piston 13 pushes the bushing 14 to move in the first direction, i.e. the Z1 direction shown in the figure. The bushing 14 contacts the flexible medium 19 and further compresses the flexible medium 19, and the flexible medium 19 compresses the metal spring 16 to achieve the pedal feel simulation of emergency braking.

[0036] In this embodiment, the pressure medium is brake fluid.

[0037] In some possible embodiments, the flexible medium is a deformable medium. Further, the flexible medium is an elastic medium, which is made of an elastic material, such as rubber; and which can be in the shape of a gasket or a spring.

[0038] For example, in this embodiment, the flexible medium is a rubber spring. In other possible embodiments, the flexible medium is a rubber gasket.

[0039] The technical scheme is adopted, the flexible medium 19 is arranged between the two rigid components of the bushing 14 and the metal spring 16 to buffer, and direct contact and collision of the bushing 14 and the metal spring 16 are prevented, noise, vibration and roughness are prevented. The roughness refers to a non-smooth or non-smooth tactile experience of a user when the pedal feeling simulation device 10 is operated. In addition, by the technical scheme, the problem that the step change of the pedal feeling is obvious when the bushing 14 and the metal spring 16 are directly contacted is improved, so that the pedal feeling is smooth and continuous force feedback, and is gradually changed instead of sudden step change. The pedal feeling is real and delicate, and the feeling of a real pedal in a real vehicle is simulated.

[0040] In some possible embodiments of the utility model, referring to Figure 1 and Figure 2 The piston 13 is cylindrical, and includes a bottom wall and a circumferential wall (not shown in the figure) extending from the bottom wall (not shown in the figure) in an axial direction, i.e. the Z direction, towards the open end 111.

[0041] Referring to Figure 5 The bushing 14 includes a head portion 141 and a main body portion 142. The piston 13 is sleeved on the outer side surface of the main body portion 142, and the main body portion 142 can slide in the axial direction, i.e. the Z direction, on the radially inner side of the circumferential wall of the piston 13. The head portion 141 of the bushing 14 can abut against the bottom wall of the piston 13 on the side facing the closed end 112. Referring to Figure 5 and in combination with Figures 1 to 4 The side of the head portion 141 of the bushing 14, which is away from the closed end 112, abuts against the flexible medium 19.

[0042] In the embodiment, the head portion 141 and the main body portion 142 of the bushing 14 are integrally formed.

[0043] Referring to Figures 2 to 4 The pedal feeling simulation device 10 further includes a compression spring 15 arranged between the main body portion 142 of the bushing 14 and the bottom wall of the piston 13.

[0044] In some possible embodiments of the utility model, referring to Figure 3 and Figure 4 An initial gap a is arranged between the head portion 141 of the bushing 14 and the end of the circumferential wall of the piston 13 in the axial direction, i.e. the Z direction. The size of the initial gap a can adjust the intervention time of the emergency brake pedal feeling. Specifically, the pressure medium enters the simulator cavity, drives the piston 13 to move, and the size of the initial gap a between the piston 13 and the bushing 14 can be adjusted to control the early or late intervention time of the metal spring 16, so as to adjust the time when the pedal feeling becomes hard during emergency braking.

[0045] In some possible embodiments of the utility model, referring to Figures 1 to 4, the flexible medium 19 is in a cylindrical or circular truncated cone shape. The flexible medium 19 is in abutment with the bushing 14 and the metal spring 16 at two ends along the axial direction thereof. The axial center of the flexible medium 19 is the same as the axial center of the bushing 14 and the metal spring 16, so that the bushing 14 does not deviate when the flexible medium 19 and the metal spring 16 are compressed, thereby avoiding uneven force.

[0046] In some possible embodiments of the utility model, the side of the head of the bushing 14 in abutment with the flexible medium 19 is planar, or the side of the head of the bushing 14 in abutment with the flexible medium 19 is provided with a central protrusion. The side of the flexible medium 19 in abutment with the head of the bushing 14 is planar.

[0047] In some possible embodiments, the side of the head of the bushing 14 in abutment with the flexible medium 19 is planar, and the side of the flexible medium 19 in abutment with the head of the bushing 14 is planar. The flat head bushing has a relatively large contact area when in contact with the flexible medium 19, and the compression amount of the flexible medium 19 has a relatively large jump, thereby realizing a change from a comfortable zone to an emergency braking zone with a relatively obvious pedal feel, and providing a customer with a pedal feel with a clear boundary.

[0048] In the embodiment, referring to Figures 1 to 5 , the side of the head of the bushing 14 in abutment with the flexible medium 19 is provided with a central protrusion 143, and the side of the flexible medium 19 in abutment with the head of the bushing 14 is planar. The bushing 14 provided with the central protrusion 143 has a relatively small contact area when in contact with the flexible medium 19, and the compression amount of the metal spring 16 is relatively small, thereby realizing a gradual compression of the metal spring 16. The side of the head of the bushing 14 in abutment is planar. The design of the bushing 14 provided with the central protrusion 143 can make the transition of the pedal feel from the comfortable zone to the emergency braking more gentle, and the size of the central protrusion 143 can be adjusted to eliminate the step feeling of the transition from the comfortable zone to the emergency braking.

[0049] In some possible embodiments of the utility model, the side of the flexible medium 19 in abutment with the metal spring 16 is planar, or the side of the flexible medium 19 in abutment with the metal spring 16 is provided with a central depression.

[0050] Specifically, referring to Figure 3 , the side of the flexible medium 19 in abutment with the metal spring 16 is planar. The flexible medium 19 has a relatively large contact area when in contact with the metal spring 16, and the compression amount of the flexible medium 19 has a relatively large jump, thereby realizing a change from a comfortable zone to an emergency braking zone with a relatively obvious pedal feel, and providing a customer with a pedal feel with a clear boundary.

[0051] In the embodiment, the metal spring 16 is punched from a metal plate, for example, a stainless steel plate, and thus can be simply manufactured. Referring to Figure 6The metal spring 16 has a first end 161 for fixed connection with the end cover 12 and a second end 162 for contact with the flexible medium 19, and a plurality of ribs 163 formed between the first end 161 and the second end 162. The elasticity of the metal spring 16 is adjusted by adjusting the size or thickness of the ribs 163.

[0052] With reference to Figure 4 The flexible medium 19 is provided with a central recess 191 on the side abutting against the metal spring 16. The shape of the central recess 191 is consistent with the shape of the second end 162 of the metal spring 16. The central recess 191 is used for accommodating the second end 162 of the metal spring 16. The flexible medium 19 and the metal spring 16 are stably connected, and the dislocation and deviation of the flexible medium 19 and the metal spring 16 are prevented, thereby affecting the simulated pedal feeling.

[0053] In some possible embodiments of the pedal feeling simulation device 10 provided by the utility model, with reference to Figure 4 The maximum outer diameter of the flexible medium 19 is equal to the inner diameter of the shell 11. In this way, when the flexible medium 19 moves along the axial direction, i.e. the Z direction, shaking and dislocation in the simulator cavity are avoided, the stability of the flexible medium 19 moving along the axial direction, i.e. the Z direction, is improved, and the stability of the pedal feeling simulation device 10 is improved.

[0054] In some possible embodiments of the pedal feeling simulation device 10 provided by the utility model, the pedal feeling simulation device 10 comprises an end cover 12, which is attached to the open end 111, and the metal spring 16 is fixedly connected to the end cover 12.

[0055] In the second aspect, with reference to Figure 7 The utility model discloses an electronic hydraulic brake system, comprising brake master cylinder 3, the pressure providing device 5 of electric control and the pressure modulation device (not shown in the drawing) for adjusting the brake pressure at each wheel, and like any one of the preceding first aspect in the embodiment, pedal feeling simulation device 10, pedal feeling simulation device 10 is communicated with brake master cylinder 3 by hydraulic line L (such as L1, L2, L3, L4, L5, L6, L7 shown in the drawing) fluidly.

[0056] In the embodiment, brake master cylinder 3 can be operated by brake pedal 1 via push rod 2. Pressure medium reservoir 4 is assigned to brake master cylinder 3, and it is under atmospheric pressure. Simulation device 6 can be jointly actuated with brake master cylinder 3. Although Figure 7 Although not shown in the drawings, but those skilled in the art can understand that the electronic hydraulic control device further comprises: a hydraulically operable wheel brake provided at each wheel; an electrically controllable pressure modulation device for adjusting the brake pressure at each wheel, comprising a normally open inlet valve and a normally closed outlet valve for each wheel brake; and an electronic control unit.

[0057] The brake pedal 1 is located in the driver's cab and can be operated by the driver, especially by their foot. The driver decelerates the vehicle by pressing down the brake pedal 1. The degree of brake pedal operation can be detected by a pedal travel sensor located on the brake pedal 1, or by other sensors that provide a signal proportional to the driver's braking operation.

[0058] The first end of the push rod 2 is fixedly connected to the brake pedal 1. The second end of the push rod 2 is fixedly connected to the piston of the master cylinder 3. In another embodiment, the master cylinder 3 may also be equipped with a vacuum booster.

[0059] exist Figure 7 In the illustrated embodiment, the master cylinder 3 has two sequentially arranged first pistons 31 and second pistons 32 within its housing. The second end of the push rod 2 is fixedly connected to the first end of the first piston 31. A first hydraulic chamber C1 is defined between the first piston 31 and the second piston 32, and a second hydraulic chamber C2 is defined between the second piston 32 and the bottom of the master cylinder 3 housing. The first hydraulic chamber C1 and the second hydraulic chamber C2 are connected to the pressure medium storage container 4 through radial holes in the pistons 31 and 32, hydraulic ports formed on the master cylinder housing, and corresponding pressure balancing lines L1 and L2. This connection can be interrupted by the relative movement of the pistons 31 and 32 within the master cylinder housing. A normally open diagnostic valve 7 is arranged in the pressure balancing line L1 between the first hydraulic chamber C1 and the pressure medium storage container 4.

[0060] A first return spring connects the second end of the first piston 31 to the first end of the second piston 32, and a second return spring connects the second end of the second piston 32 to the bottom of the master cylinder housing. When the master cylinder 3 is not operated, the return springs position the first piston 31 and the second piston 32 in their initial positions. The push rod 2 couples the oscillating motion of the brake pedal 1 with the translational motion of the first piston 31. The actuation stroke of the first piston 31 is acquired by a displacement sensor, preferably implemented as redundant. Thus, the corresponding piston stroke signal is also a measure of the degree of brake pedal operation.

[0061] Additionally, the first hydraulic chamber C1 and the second hydraulic chamber C2 are respectively connected to one of the two brake circuit supply lines via additional hydraulic ports formed on the master cylinder housing and corresponding hydraulic lines L3 and L4. A normally open master cylinder isolation valve (not shown in the figure) is arranged between the first hydraulic chamber C1, the second hydraulic chamber C2, and the corresponding brake circuit supply line. In online control mode, the electronic control unit closes the master cylinder isolation valve to block the hydraulic connection between the first hydraulic chamber C1, the second hydraulic chamber C2, and the corresponding brake circuit supply line of the brake master cylinder 3.

[0062] It should be understood that this utility model is not limited to the following. Figure 7The shown tandem master brake cylinder also applies to the case where the master brake cylinder has only one master cylinder piston.

[0063] The electrically controllable pressure provider 5 can comprise a cylinder-piston assembly with a pressure chamber, the piston of which can be moved by a motor M via a rotary-translatory transmission. The pressure generated by the piston pressurizing a pressure medium in the pressure chamber is fed into the system pressure line L5. The system pressure line L5 is connected to both brake circuit supply lines, between the system pressure line L5 and each brake circuit supply line there is arranged a normally closed on valve (not shown in the drawing). In online brake mode, the electronic control unit opens the on valves, and pressure medium reaches the brake circuit supply lines and further the wheel brakes from the pressure chamber of the electrically controllable pressure provider 5. The pressure chamber of the electrically controllable pressure provider 5 is further connected via a connection line L6 to the pressure medium reservoir 4. Thus, upon closing of the on valves, pressure medium can be sucked into the pressure chamber by return of the piston.

[0064] In some possible embodiments of the utility model, an electrically controllable, normally closed simulator valve 8 is arranged in the hydraulic line L. Exemplarily, with reference to Figure 7 , the simulator 6 can be hydraulically connected to the master brake cylinder 3, for example its simulator chamber can be connected to the first hydraulic chamber C1 of the master brake cylinder 3 via the hydraulic line L7. A normally closed simulator valve 8 is arranged in the hydraulic line L7. Upon pedal force input and opening of the simulator valve 8, pressure medium flows from the first hydraulic chamber C1 of the master brake cylinder 3 into the simulator chamber of the simulator 6 to provide the driver with a comfortable brake pedal feeling in online brake mode. A check valve is arranged in parallel to the simulator valve 8, which enables pressure medium to flow back from the simulator chamber to the first hydraulic chamber C1 of the master brake cylinder as unhindered as possible, regardless of the switching state of the simulator valve 8. Other connection schemes of the simulator to the master brake cylinder 3 are conceivable.

[0065] In Figure 7 the shown electronic hydraulic brake system, the simulator 6 is provided with a flexible medium 19 between the metal spring 16 and the bushing 14 in the simulator chamber thereof, and the metal spring 16 and the bushing 14 clamp the flexible medium 19. The flexible medium 19 prevents noise, vibration and roughness caused by direct contact and collision between the bushing 14 and the metal spring 16. The provision of the flexible medium 19 also improves the problem that the step change of the pedal feeling is obvious when the bushing 14 and the metal spring 16 are in direct contact, so that the pedal feeling is a smooth and continuous force feedback, which is gradually changed rather than suddenly changed in steps. In addition, in the utility model, since the hardness of the metal spring 16 is not affected by temperature, the pedal feeling of the pedal feeling simulator 10 is stable even in different regions or seasons.

[0066] In a third aspect, embodiments of the present application disclose an automobile comprising the electronic hydraulic brake system according to any one of the embodiments of the second aspect.

[0067] Although the present application has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by the skilled in the art that the foregoing is a further detailed description of the present application in connection with the specific embodiments, and the present application is not limited to these descriptions. The skilled in the art can make various changes in form and details without departing from the spirit and scope of the present application, including making several simple deductions or substitutions.

Claims

1. A pedal feel simulation device characterized by comprising: The pedal feel simulator comprises: a housing having an open end and a closed end, the housing defining a simulator cavity; a piston disposed in the simulator cavity, the piston and the closed end defining a hydraulic chamber to which pressure medium from a brake master cylinder can be supplied, the pressure medium being capable of generating pressure and acting on the piston to urge the piston to move; a bushing disposed in the simulator cavity on a side of the piston facing away from the hydraulic chamber; a metal spring disposed between the open end and the bushing; a flexible medium disposed between the bushing and the metal spring, the bushing and the metal spring clamping the flexible medium.

2. The pedal feel simulation apparatus of claim 1, wherein The piston is cylindrical and comprises a bottom wall and a circumferential wall extending axially from the bottom wall towards the open end; The bushing comprises a head portion and a body portion, the body portion being axially slidable on the radially inner side of the circumferential wall of the piston, the head portion abutting the flexible medium; The pedal feel simulator further comprises a compression spring disposed between the body portion of the bushing and the bottom wall of the piston.

3. The pedal feel simulation apparatus of claim 2, wherein The flexible medium is cylindrical or frustoconical, and abuts the bushing and the metal spring at opposite axial ends thereof.

4. The pedal feel simulation apparatus of claim 3, wherein The side of the head portion of the bushing abutting the flexible medium is planar, or the side of the head portion of the bushing abutting the flexible medium is provided with a central protrusion; The side of the flexible medium abutting the head portion of the bushing is planar.

5. The pedal feel simulation apparatus of claim 3, wherein The side of the flexible medium abutting the metal spring is planar, or the side of the flexible medium abutting the metal spring is provided with a central recess.

6. The pedal feel emulation apparatus of claim 3, wherein The maximum outer diameter of the flexible medium is equal to the inner diameter of the housing.

7. The pedal feel emulation apparatus of claim 1, wherein The pedal feel simulator further comprises an end cap attached to the open end, the metal spring being fixedly connected to the end cap.

8. An electro-hydraulic brake system characterized by, The pedal feel simulator is fluidly connected to the brake master cylinder by means of a hydraulic line.

9. The electro-hydraulic brake system of claim 8, wherein, The hydraulic line is provided with an electrically operable, normally closed simulator valve.

10. An automobile characterized by comprising: The electronic hydraulic brake system comprises the pedal feel simulator according to any one of claims 1 to 7. The electronic hydraulic brake system comprises the pedal feel simulator according to any one of claims 8 or 9.

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