JPH04122269U - master cylinder - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to provide a master cylinder that requires fewer parts in the guide device and that allows for easier dimensional control than in the past. [Structure] A cylinder body 1 has a cylinder hole 2 in which a large diameter portion 2B is formed with a stepped portion 9 interposed in the opening, and a cylinder body 1 is slidably inserted into the cylinder hole 2 and defines a pressure chamber C within the cylinder hole. The guide device 7 includes a piston 15 having a head 15A and a shaft portion 15B extending outward from the cylinder hole, and a guide device provided between the shaft portion and the large diameter portion of the piston.
In the master cylinder, the master cylinder has a plate 4 that engages with the step, a lip seal 5 adjacent to the plate, a seal backup 6, and a backup retainer 8, one end of which is connected to the head of the piston. Protrusions 12 and 13 are formed on the inner peripheral side of the plate 4 so that their end sides can abut on the inner lip 5D of the seal, respectively, and project in both axial directions.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is based on a brake or clutch device used in vehicles, etc. Regarding the star cylinder.

0002

[Conventional technology]

This type of master cylinder was previously disclosed in Japanese Utility Model Application Publication No. 58-160865. There is something written. The cylinder hole that the cylinder body of this master cylinder has The opening side is formed with a larger diameter than the other part, and the shaft of the piston passes through this large diameter part. It houses a guiding device.

0003

[Problem that the idea aims to solve]

This guide device is a lip type seal on which the shaft of the piston slides, creating a tight seal between it and the shaft. At the same time as sealing the piston when returning (or before installing it in the vehicle, etc.) It has the role of a stopper to receive the head of the cylinder, but when the cylinder is operated, the The lip type seal behaves under negative pressure, and during this behavior, the inner lip pulls into the pressure chamber. Do not do this because there is a risk that external air may enter the cylinder hole due to leakage and loss of sealing performance. It is necessary to prevent the behavior of lip-type seals.

0004 However, in an attempt to prevent this behavior of the seal and have it serve as the stopper described above, As a result, the structure of the guide device becomes complex and the number of parts increases, making dimensional management troublesome. The problem arises that

[0005] This invention was devised to solve this problem, and the number of parts of the guide device is reduced. A master cylinder that does not need to be used and makes dimension control easier than before. The purpose is to provide.

[0006]

[Means to solve the problem] In order to achieve the above object, the present invention has a piston attached to the plate constituting the guide device. A contactable protrusion is formed on the head of the seal and on the inner lip of the seal.

[0007]

[Effect]

In this invention, one plate serves as both a piston stopper and a cup seal holder. Ru.

[0008]

【Example】

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

[0009] In Fig. 1, 1 is the cylinder body of a tandem master cylinder, with one end open. The opening side of the cylinder hole 2 extends over a predetermined length, and the other part 2A It has a large diameter part 2B with a larger diameter, and a plate 4 and a lip are attached to this large diameter part 2B. A guide device 7 consisting of a push-type seal 5 and a seal backup 6 is installed at the opening end of the cylinder hole. It is stored with a fitted stopper ring 8 to prevent it from coming off. Plate 4 is the other part 2 The seal 5 engages with the stepped portion 9 that borders the large diameter portion 2B and the seal backup 6. It is fitted into an annular groove 6A formed in the plate 4 and engaged with the plate 4.

0010 The plate 4 is a ring body having a central hole 10, as shown in FIGS. 2 and 3. , a through hole 11 is formed near the outer periphery, and a projection (piston) protruding from one surface is formed on the inner periphery side. (becomes a ton stopper) 12 and a protrusion 13 protruding from the back (becomes a seal holder) are formed alternately and at predetermined intervals in the circumferential direction, and the inner lip of the seal 5 5D is engaged with the protrusion 13. These protrusions 12 and 13 have a table-like shape as shown in FIG. are doing.

[0011] The cylinder hole 2 has a slave piston 14 on its bottom side and a main piston 15 on its opening side. The heads 15A of the two are connected to each other by bolts 16 so as to be movable relative to each other and are slidably inserted. and are urged toward the opening side by return springs 17 and 18, respectively.

0012 The slave piston 14 defines a slave pressure chamber A between it and the bottom of the cylinder hole 2. A liquid supply chamber B is defined between the sliding parts 19 and 20 and the inner peripheral surface of the cylinder hole 2. S The cylinder body 1 has a loosening hole 22 that opens to the bottom of the reservoir connection part 21 and the slave pressure chamber A. A through hole 23 is formed that opens to the bottom of the reservoir connection part 21 and the liquid replenishment chamber B. . 24 is a lip type seal fitted adjacent to the sliding part 19; It is a lip-type sticker that has been worn. The main piston 15 has an outer peripheral portion 1 of its head 15A. 5a has an axial through hole 26 formed in the head 15A, and the head 15A is connected to the slave piston 14. A shaft-shaped portion 15B extending from the head 15A and defining a main pressure chamber C therebetween is connected to the guide device 7. In between, a liquid replenishment chamber D with one end of the through hole 26 open is defined and penetrated through the guide device 7. and extends outward from the opening of the cylinder hole 2. The other end of the through hole 26 is the tip of the head 15A. It is closed with a lip type seal 27 fitted to the portion 15c. to cylinder body 1 is the bottom of the reservoir connection part 28 and the loosening hole 29 that opens to the main pressure chamber C, and the reservoir connection part 28. A through hole 30 that opens to the bottom of the connecting portion 28 and the liquid supply chamber D is formed. Above bolt 1 The threaded end of 6 is screwed into the side of the main pressure chamber C of the head 15A, and the head side is connected to the slave piston 14. It loosely penetrates the retainer 31 which is pressed by the return spring 18 to the side of the main pressure chamber C. There is. 32 is a spring receiver that receives one end of the return spring 18, and also serves to hold down the seal 27. Sleeping.

[0013] The head body portion 15b of the main piston 15 on the inner circumferential side than the outer circumferential portion 15a is the outer circumferential portion 15. The wall is thicker toward the cylinder hole 2 opening side than a, and when the cylinder is not in operation, this head The side surface of the cylinder hole 2 opening of the body portion 15b is in pressure contact with the protrusion 12 of the plate 4. In this embodiment, a portion 2A of the cylinder hole 2 on which the main piston 15 slides and a guide device 7. A member that engages with the stepped portion 9 that borders the large diameter portion 2B on the open end side that accommodates the 4, and the inner lip 5D of the lip seal 5 of the guide device 7 is attached to this plate 4. Since the protrusion 13 for receiving or pressing is formed, when the piston returns, the cylinder Even when the negative pressure is generated in the hole 2A, the inner circumference of the lip seal 5 is caused by the negative pressure. This prevents the phenomenon of the pump 5D being drawn in, and prevents air from being drawn into the pressure chamber. It can be prevented.

[0014] Moreover, since the protrusion 12 of this plate 4 serves as a piston stopper, one plate Rate 4 prevents air intake and acts as a piston stopper. Since the configuration of the guide device 7 is simplified, dimensional management becomes easier.

[0015]

[Effect of the idea]

As explained above, in this invention, one plate has a piston stopper and a cup seal. Since it also serves as a lever holder, the number of parts for the guide device is reduced, and the dimensions are smaller than before. Easier to manage.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of the plate in the above embodiment.

FIG. 3 is a view taken along arrow A in FIG. 2;

FIG. 4 is a diagram showing protrusions on the plate in the above embodiment.

[Explanation of symbols]

1 Cylinder body 2 Cylinder hole 2B Large diameter part 4 plate 5 Lip type seal 5D Inner lip of lip type seal 6 Seal back upper 7 Guidance device 8 Stopper ring 9 Step part 12 Protrusion 13 Protrusion

Claims (1)

[Scope of utility model registration request] 1. A cylinder body having a cylinder hole having a large diameter portion with a step interposed in the opening, a head slidably inserted into the cylinder hole and defining a pressure chamber within the cylinder hole, and a cylinder. A plate comprising: a piston having a shaft portion extending outward from the hole; and a guide device provided between the shaft portion and the large diameter portion of the piston, the guide device engaging with the stepped portion;
In a master cylinder having a lip type seal adjacent to a plate, a seal backup, and a backup retainer, one end can be brought into contact with the head of the piston, and the other end can be brought into contact with the inner lip of the seal. The master cylinder is configured such that a protrusion is formed on the inner peripheral side of the plate so as to protrude in both axial directions.