Hydraulic pressure generation device

Abstract

A hydraulic pressure generation device (1) is provided with: a housing (10) in which a cylinder hole (11) is opened in a prescribed opening surface (100); a piston (12) which is disposed in the cylinder hole (11); and a cover (20) which is attached to the opening surface (100) so as to cover the opening of the cylinder hole (11), and which partitions, with the housing (10) and the piston (12), a hydraulic chamber the volume of which changes due to the movement of the piston (12). The cover (20) is coupled to the opening surface (100) of the housing (10) by friction welding.

Description

Hydraulic generating device

[0001] The present disclosure relates to a hydraulic generating device.

[0002] Patent Document 1 discloses a technique in which a cylinder hole is opened on a first surface of a hydraulic block, and a tubular cylinder cover is disposed on a second surface located on the opposite side of the first surface to extend the cylinder hole. In Patent Document 1, the cylinder cover is coupled to the hydraulic block by a surrounding caulking portion.

[0003] German Patent Application Publication No. 102021210766

[0004] However, when the cylinder cover (hereinafter referred to as the cover) is coupled to the housing of the hydraulic block by caulking, it is necessary to properly caulk the entire circumference of the hydraulic chamber, and it is difficult to ensure airtightness.

[0005] In order to solve the above problems, a hydraulic generating device according to an aspect of the present disclosure includes a housing having a cylinder hole opened on a predetermined opening surface, a piston disposed in the cylinder hole, and a cover attached to the opening surface so as to cover the opening of the cylinder hole and partitioning a hydraulic chamber whose volume changes by the movement of the piston together with the housing and the piston. In the hydraulic generating device, the cover is coupled to the opening surface of the housing by frictional pressure contact.

[0006] According to an aspect of the present disclosure, airtightness can be easily ensured when the cover is coupled to the housing.

[0007] It is a schematic diagram showing a configuration example of a hydraulic generating device according to Embodiment 1 of the present disclosure. It is an enlarged view showing an example of a first coupling portion and a second coupling portion. It is a plan view showing an example of an opening surface according to Embodiment 1 of the present disclosure. It is a schematic diagram showing a configuration example of a hydraulic generating device according to Embodiment 2 of the present disclosure. It is a plan view showing an example of an opening surface according to Embodiment 2 of the present disclosure. It is a schematic diagram showing a configuration example of a hydraulic generating device according to Embodiment 3 of the present disclosure. It is a plan view showing an example of an opening surface according to Embodiment 3 of the present disclosure. It is a schematic diagram showing a configuration example of a hydraulic generating device according to Embodiment 4 of the present disclosure. It is an enlarged view showing a modified example of a first coupling portion and a second coupling portion.

[0008] [Embodiment 1] Figure 1 is a schematic diagram showing one example of the configuration of a hydraulic pressure generating device according to Embodiment 1 of the present disclosure. The hydraulic pressure generating device 1 shown in Figure 1 comprises a housing 10, a piston 12, a linear motion conversion mechanism 13, and a cover 20.

[0009] The housing 10 is made of a metal material including aluminum alloy or iron. The housing 10 has a cylinder bore 11 opening in a predetermined opening surface 100. In Figure 1, S1 is the central axis of the cylinder bore 11. The piston 12 is positioned inside the cylinder bore 11. The piston 12 is coaxial with the cylinder bore 11. The piston 12 is slidable within the cylinder bore 11 in a direction parallel to the central axis S1 of the cylinder bore 11. Hereinafter, the direction parallel to the central axis S1 of the cylinder bore 11 will be referred to as the axial direction of the cylinder bore 11. The linear motion conversion mechanism 13 is, for example, a screw mechanism and has a rotating part 130 and a linear motion part 131. The rotating part 130 is, for example, a screw shaft and is coaxial with the cylinder bore 11. The rotating part 130 rotates in conjunction with the rotating shaft of an electric motor, etc. The linear motion part 131 converts the rotation of the rotating part 130 into linear motion. The piston 12 moves linearly in conjunction with the linear motion part 131.

[0010] The cover 20 is cylindrical and covers the cylinder bore 11. The cover 20 is made of a metal material such as an aluminum alloy or iron. The cover 20 has a hole 20A on the surface facing the opening surface 100 of the cylinder bore 11. The hole 20A is connected to the cylinder bore 11. The opening diameter of the hole 20A is larger than the opening diameter of the cylinder bore 11. The cover 20 surrounds the opening of the hole 20A with an annular first connecting portion 22. The first connecting portion 22 of the cover 20 is an example of a contact portion that contacts the opening surface 100 of the housing 10.

[0011] The opening surface 100 of the housing 10 is provided with a second coupling portion 102 that surrounds the outer circumference of the cylinder hole 11. The second coupling portion 102 is an example of a contacted portion that contacts a contact portion. The second coupling portion 102 is, for example, a groove into which the first coupling portion 22 of the cover 20 is inserted. The first coupling portion 22 of the cover 20 is an example of a projection that fits into the groove. When the first coupling portion 22 is coupled to the second coupling portion 102 by friction pressure, the hole 20A is connected to the cylinder hole 11, and the cylinder hole 11 is extended to the inside of the cover 20.

[0012] The cover 20, to which the first coupling portion 22 is coupled to the second coupling portion 102, partitions the hydraulic chamber together with the housing 10 and the piston 12. The cover 20 has a first bottom portion 21 facing the cylinder bore 11. An inner circumferential side wall 21A extends from the outer circumference of the first bottom portion 21 toward the opening surface 100 of the housing 10 along the central axis S1 of the cylinder bore 11. Inside the cover 20, a cylindrical first hydraulic chamber 30 is partitioned by the first bottom portion 21 and the inner circumferential side wall 21A. In the cover 20, the first bottom portion 21 and the inner circumferential side wall 21A are examples of hydraulic chamber partitions, are formed in a bottomed cylindrical shape, and form the first hydraulic chamber 30. This first hydraulic chamber 30 constitutes a part of the hydraulic chamber partitioned by the housing 10, the cover 20, and the piston 12. The first joint portion 22 of the cover 20, which is an example of a contact portion, extends from the end of the hydraulic chamber compartment that forms the first hydraulic chamber 30 and contacts the opening surface 100 of the housing 10.

[0013] In Embodiment 1, the inner circumferential side wall 21A that partitions the first hydraulic chamber 30 is coaxial with the cylinder bore 11. The hydraulic chamber extends from the first hydraulic chamber 30 partitioned within the hole 20A of the cover 20 to the piston 12 within the cylinder bore 11. The cover 20 extends the hydraulic chamber partitioned within the cylinder bore 11 by the piston 12 to the first hydraulic chamber 30. As the piston 12 slides within the cylinder bore 11 in conjunction with the linear motion of the linear motion unit 131, the volume of the hydraulic chamber changes. As the linear motion unit 131 and the piston 12 move toward the cover 20, the volume of the hydraulic chamber decreases and the hydraulic pressure inside the hydraulic chamber increases.

[0014] A fluid passage 101 is connected to the opening surface 100 of the housing 10, which communicates with the first hydraulic chamber 30, which is part of the hydraulic chamber. The hydraulic pressure generator 1 discharges fluid from the hydraulic chamber, including the first hydraulic chamber 30, via this fluid passage 101. For example, if the hydraulic pressure generator 1 is installed in a braking system, the fluid passage 101 discharges fluid to the master cylinder, wheel cylinder, etc.

[0015] A connecting passage 31 is provided between the cover 20 and the opening surface 100 of the housing 10, connecting the first hydraulic chamber 30 and the fluid passage 101. The connecting passage 31 extends from the first hydraulic chamber 30 in a direction perpendicular to the central axis S1 of the cylinder bore 11 and is provided by the first coupling portion 22 and the second bottom portion 23 of the cover 20. The second bottom portion 23 is closer to the opening surface 100 of the housing 10 than the first bottom portion 21. Therefore, the fluid in the hydraulic chamber is smoothly guided to the fluid passage 101.

[0016] Figure 2 is an enlarged view showing an example of the first and second joints. The second joint 102 shown in Figure 2 is an example of a groove. The first joint 22 shown in Figure 2 is an example of a protrusion. In Figure 2, the first joint 22 is inserted inside the second joint 102. As shown in Figure 2, the first joint 22 inserted into the second joint 102 is installed such that its inner circumferential side wall 22A abuts against the inner circumferential side wall 102A of the second joint 102, or has a gap that prevents the molten material from entering. The outer circumferential side wall 22B on the opposite side of the inner circumferential side wall 22A has a larger gap between it and the outer circumferential side wall 102B of the second joint 102 than the gap between the inner circumferential side wall 102A and the first joint 22.

[0017] When the first joint 22 is friction-pressed against the second joint 102, the cover 20 is rotated around the central axis S1 as the center of rotation. This rotation causes the inner circumferential side walls 22A of the first joint 22 and the inner circumferential side wall 102A of the second joint 102, which are in contact with each other, to rub against each other, generating frictional heat. This frictional heat causes at least one of the first joint 22 and the second joint 102 to melt. The molten material generated at this time flows into the gap between the outer circumferential side wall 22B of the first joint 22 and the outer circumferential side wall 102B of the second joint 102 and accumulates in the groove of the second joint 102. Because the molten material flows into the gap between the outer circumferential side wall 22B of the first joint 22 and the outer circumferential side wall 102B of the second joint 102, it is difficult for the molten material to flow into the cylinder hole 11.

[0018] The first connecting portion 22 is pressed against the second connecting portion 102, and frictional heat is generated by rotating at least one of the first connecting portion 22 and the second connecting portion 102. Then, the rotation of the first connecting portion 22 and the second connecting portion 102 is stopped, and they are pressed in a direction that brings them closer together. Once cooled, the first connecting portion 22 is connected to the second connecting portion 102.

[0019] Figure 3 is a plan view showing an example of an opening surface according to Embodiment 1 of the present disclosure. As shown in Figure 2, the opening of the cylinder hole 11 is located within the opening of the hole 20A. The first coupling portion 22 of the cover 20 surrounds the outer circumference of the hole 20A. As shown in Figure 3, in plan view, the first coupling portion 22 of the cover 20 is annular with respect to the central axis S1. As shown in Figures 1 and 3, the cover 20 has a point-symmetric shape with respect to the central axis S1 and a line-symmetric shape with respect to a straight line perpendicular to the central axis S1. Therefore, while the cover 20 rotates around the central axis S1 of the cylinder hole 11, the inner circumferential side wall 22A of the first coupling portion 22 continuously and evenly rubs against the inner circumferential side wall 102A of the second coupling portion 102, generating frictional heat evenly.

[0020] [Embodiment 2] Embodiment 2 of the present disclosure will be described below. For the sake of convenience of explanation, components having the same function as those described in Embodiment 1 will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0021] Figure 4 is a schematic diagram showing an example configuration of a hydraulic pressure generator according to Embodiment 2 of the present disclosure. Figure 5 is a plan view showing an example of an opening surface according to Embodiment 2 of the present disclosure. In the hydraulic pressure generator 1 according to Embodiment 2, the inner circumferential side wall 21A that partitions the first hydraulic pressure chamber 30 is not coaxial with the cylinder bore 11. As shown in Figures 4 and 5, in the hydraulic pressure generator 1 according to Embodiment 2, the central axis S2 of the inner circumferential side wall 21A is located on the side of the fluid passage 101 that is centrally located than the central axis S1 of the cylinder bore 11. When the first coupling portion 22 is frictionally pressed against the second coupling portion 102, the cover 20 is rotated with the central axis S2 as the center of rotation. By positioning the central axis S2 of the inner circumferential side wall 21A on the side of the fluid passage 101 that is centrally located than the central axis S1 of the cylinder bore 11, the diameter of the hole 20A in the cover 20 can be made smaller than that of Embodiment 1.

[0022] [Embodiment 3] Embodiment 3 of the present disclosure will be described below. For the sake of convenience of explanation, components having the same function as those described in Embodiments 1 and 2 will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0023] Figure 6 is a schematic diagram showing an example configuration of a hydraulic pressure generating device according to Embodiment 3 of the present disclosure. Figure 7 is a plan view showing an example of an opening surface according to Embodiment 3 of the present disclosure. In the hydraulic pressure generating device 1 according to Embodiment 3 of the present disclosure, when the first coupling portion 22 is frictionally pressed against the second coupling portion 102, the first coupling portion 22 is not rotated, but the annular rotating member 40 is rotated.

[0024] The first joint portion 22 of the cover 20 shown in Figure 6 is an example of a protruding portion, and it protrudes radially outward from the first hydraulic chamber 30. In Figure 6, the outer peripheral edge 22C of the first joint portion 22 and the inner peripheral side wall 21A of the second joint portion 102 are in contact with the inner peripheral surface 40A of the annular rotating member 40. At this time, the outer peripheral edge 22C of the first joint portion 22 of the cover 20 is flush with the inner peripheral side wall 21A of the second joint portion 102.

[0025] The rotating member 40 is made of an aluminum alloy, a metal material including iron, resin, etc. The rotating member 40 is coaxial with the cylinder bore 11. When the first joint 22 is friction-pressed against the second joint 102 using the rotating member 40, the rotating member 40 is rotated around the central axis S1 of the cylinder bore 11. When the rotating member 40 rotates around the central axis S1, the inner circumferential surface 40A of the rotating member 40 rubs against the outer peripheral edge 22C of the first joint 22 of the cover 20 and the inner circumferential side wall 21A of the second joint 102, generating frictional heat. The rotating member 40 melts due to this frictional heat. The molten material generated when the rotating member 40 melts flows into the gap between the rotating member 40 and the outer peripheral side wall 102B of the second joint 102 and accumulates in the groove of the second joint 102. Because the molten material is designed to flow into the gap between the rotating member 40 and the outer peripheral side wall 102B of the second joint 102, it is difficult for the molten material to flow into the cylinder hole 11.

[0026] The rotating member 40 has a clamping portion 40B that clamps the peripheral edge of the first connecting portion 22, including the outer peripheral edge 22C of the first connecting portion 22, between itself and the opening surface 100 of the housing 10. When the first connecting portion 22 is frictionally pressed against the second connecting portion 102, the clamping portion 40B presses the first connecting portion 22 against the opening surface 100. As a result, the outer peripheral edge 22C of the first connecting portion 22 connects to the vicinity of the opening of the second connecting portion 102.

[0027] As shown in Figure 7, in a plan view, the cover 20 according to Embodiment 3 is not circular, but has an irregular shape with a protruding second bottom portion 23 that demarcates the communication passage 31. Such an irregularly shaped cover 20 is difficult to rotate without wobbling during friction welding. In the hydraulic pressure generating device 1 according to Embodiment 3, a rotating member 40 is rotated instead of the first joint portion 22, so the first joint portion can be friction-welded to the second joint portion regardless of the shape of the cover 20.

[0028] [Embodiment 4] Embodiment 4 of the present disclosure will be described below. For the sake of convenience of explanation, components having the same function as those described in Embodiments 1 to 3 above will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0029] Figure 8 is a schematic diagram showing one example configuration of a hydraulic pressure generating device according to Embodiment 4 of the present disclosure. As shown in Figure 8, in the hydraulic pressure generating device 1 according to Embodiment 4 of the present disclosure, the second coupling portion 102 is not a groove portion, but a part of the opening surface 100. In the hydraulic pressure generating device 1 according to Embodiment 4, the rotating member 40 according to Embodiment 4 is arranged on a part of the opening surface 100 that forms the second coupling portion 102. The inner circumferential surface 40A of the rotating member 40 according to Embodiment 4 is in contact with the outer circumferential edge portion 22C of the first coupling portion 22 according to Embodiment 4.

[0030] [Modification] In embodiments 1 to 4 described above, the cover 20 has a first bottom portion 21, and the cylindrical first hydraulic chamber 30 is partitioned by the first bottom portion 21 and the inner circumferential side wall 21A. However, the cover 20 does not need to have a first bottom portion 21 as long as it can partition the hydraulic chamber together with the housing 10 and the piston 12. For example, the inner circumferential side wall 21A of the cover 20 may be provided such that one end faces the cylinder hole 11 and the other end faces another cylinder hole or other parts of the housing 10.

[0031] In embodiments 1 to 4 described above, the second connecting portion 102 is a groove, and the first connecting portion 22 is a projection that is inserted into the groove. However, the opening surface 100 may not have a groove into which the first connecting portion 22 is inserted, and the opening surface 100 and the first connecting portion 22 may be joined by friction welding. This eliminates the cost of creating a groove, thus enabling inexpensive sealing. Alternatively, the first connecting portion 22 may be a groove, and the second connecting portion 102 may be a projection. If a groove is provided in the first connecting portion 22, it may be provided on the outer peripheral edge 22C, or on the surface facing the opening surface 100 or the opposite surface. If the groove of the first connecting portion 22 is provided on the surface facing the opening surface 100, the second connecting portion 102, which is a projection, may be inserted into the groove. If the groove of the first connecting portion 22 is provided on the outer peripheral edge 22C, the clamping portion 40B of the rotating member 40 may be inserted. Furthermore, if a groove is provided on the surface of the first connecting portion 22 opposite to the surface facing the opening surface 100, the second connecting portion 102 may be brought into contact with the outer peripheral edge 22C of the first connecting portion 22, so that one end of the rotating member 40 is inserted into the groove and the other end contacts the opening surface 100. Alternatively, the second connecting portion 102 may be made into a projection, and the outer peripheral edge 22C of the first connecting portion 22 may be brought into contact with the side surface of the second connecting portion 102. Figure 9 is an enlarged view showing modified examples of the first and second connecting portions. The second connecting portion 102 shown in Figure 9 is a projection that protrudes from the opening surface 100. The first connecting portion 22 shown in Figure 9 has a surface 22D that contacts the opening surface 100, and its outer peripheral edge 22C contacts the inner peripheral side wall 102A of the second connecting portion 102. The rotating member 40 shown in Figure 9 is annular in shape, and its bottom surface 40C, which faces the opening surface 100, abuts against the tip surface 22E of the first joint 22 and the tip surface 102C of the second joint 102. The inner circumferential surface 40A of the rotating member 40 is located radially inward from the tip surface 22E of the first joint 22. The outer circumferential surface 40D of the rotating member 40 is located radially outward from the tip surface 102C of the second joint 102. The first joint 22 and the second joint 102 have gaps that allow molten material to flow into the inner circumferential surface 40A side and the outer circumferential surface 40D side of the rotating member 40. When the rotating member 40 is rotated, the bottom surface 40C of the rotating member 40 rubs against the tip surface 22E of the first joint 22 and the tip surface 102C of the second joint 102, generating frictional heat.The molten material, which melts due to frictional heat from the rotating member 40, flows into the gap between the inner circumferential surface 40A and the outer circumferential surface 40D of the rotating member 40. This configuration makes it easy to ensure airtightness between the cover 20 and the housing 10. By making the second coupling portion 102 a protruding portion that extends from the opening surface 100, the amount of frictional heat generated by the rotation of the rotating member 40 that is released throughout the housing 10 is reduced. This allows the first coupling portion 22 to be efficiently coupled to the second coupling portion 102. The bottom surface 40C of the rotating member 40 may abut either the tip surface 22E of the first coupling portion 22 or the tip surface 102C of the second coupling portion 102, with a gap between them. This allows the molten material to flow between the other side and the bottom surface 40C of the rotating member 40.

[0032] In embodiments 3 and 4 and their modifications, the rotating member 40 is melted by the frictional heat generated by the rotation of the rotating member 40, thereby producing molten material. However, the melting caused by the frictional heat generated by the rotation of the rotating member 40 is not limited to the rotating member 40. The molten material can be produced by the melting of at least one of the rotating member 40, the cover 20, and the housing 10 due to the frictional heat generated by the rotation of the rotating member 40.

[0033] [Summary] A hydraulic pressure generator according to one aspect of the present disclosure comprises a housing having a cylinder hole opening in a predetermined opening surface, a piston disposed in the cylinder hole, and a cover attached to the opening surface so as to cover the opening of the cylinder hole, and partitioning a hydraulic chamber whose volume changes with the movement of the piston together with the housing and the piston, wherein the cover is joined to the opening surface of the housing by friction welding. When the cover is joined to the housing by crimping, it is necessary to properly crimp the entire circumference of the hydraulic chamber, making it difficult to ensure airtightness. Friction welding, due to its processing method, makes it easier to ensure airtightness between the cover and the housing and can suppress liquid leakage from the connection part between the cover and the housing.

[0034] A hydraulic pressure generator according to one aspect of the present disclosure, in the above aspect, includes a rotating member that is rotated when joining the cover and the housing, wherein the cover and the housing are joined by a molten material formed by frictional heat generated when the rotating member rubs against at least one of the cover and the housing, causing the rotating member, the cover, and the housing to melt. The rotating member is rotated, and the joint is formed by a molten material formed by frictional heat generated when the rotating member rubs against at least one of the cover and the housing. Because the rotating member is rotated when friction welding is performed, the design freedom for the shape of the cover and the housing can be increased.

[0035] In one aspect of the present disclosure, the hydraulic pressure generating device, in the above embodiment, has a projection on at least one of the cover and the housing that protrudes outward from the hydraulic chamber, and the cover and the housing are joined by a molten material melted by frictional heat generated when the rotating member rubs against the projection. The cover and the housing have a projection on at least one of the cover and the housing that protrudes outward from the hydraulic chamber. The cover and the housing are joined by a molten material melted by frictional heat generated when the rotating member rubs against this projection. By making the part where the rotating member rubs against the housing protrude outward from the hydraulic chamber, the amount of frictional heat released to the entire housing can be reduced. This makes it possible to efficiently join the cover to the housing by friction welding.

[0036] In one aspect of the present disclosure, the hydraulic pressure generating device, in the above embodiment, has a groove that fits with the other of either the contact portion of the cover that contacts the opening surface of the housing or the contacted portion of the housing that contacts the contact portion of the cover, and the other of the contact portion and the contacted portion has a projection that fits with the groove, and the cover and the housing are joined by the molten material flowing into the groove. When friction welding is performed, the molten material accumulates in the groove, making it difficult for the molten material to enter the hydraulic chamber.

[0037] In one aspect of the present disclosure, a hydraulic pressure generating device, in the above embodiment, has a groove that fits with the other of either the contact portion of the cover that contacts the opening surface of the housing or the contacted portion of the housing that contacts the contact portion of the cover, and the other of the contact portion or the contacted portion has a projection that fits with the groove, and the cover and the housing are joined by molten material from at least one of the cover and the housing flowing into the groove. When friction welding is performed, molten material accumulates in the groove, making it difficult for molten material to enter the hydraulic chamber.

[0038] In one aspect of the present disclosure, the hydraulic pressure generating device, in the above embodiment, has a cover that is formed in the shape of a bottomed cylindrical part and partitions the hydraulic pressure chamber, and a contact part that extends from the end of the hydraulic pressure chamber partition and contacts the opening surface of the housing. The cylinder hole is connected to the hydraulic pressure chamber partition of the cover by the contact part that extends from the end of the hydraulic pressure chamber partition and contacts the opening surface of the housing. As a result, the hydraulic pressure chamber partitioned in the cylinder hole can be expanded into the cover.

[0039] [Other Technical Ideas] Next, we will describe the technical ideas that can be understood from the above embodiments and modified examples. (a) The hydraulic pressure generating device according to claim 1, wherein either the contact portion of the cover that contacts the opening surface of the housing or the contacted portion of the housing that contacts the contact portion of the cover has a groove and the other has a protrusion, the protrusion is inserted into the groove, or the outer peripheral edge of the protrusion is connected to the inner peripheral side wall of the groove, and the cover and the housing are joined by a rotating member that abuts the outer peripheral edge or by a molten material melted by frictional heat generated by rotating the protrusion. (b) The hydraulic pressure generating device according to (a), wherein the side wall of the groove on the cylinder hole side is joined to the other of either the contact portion of the cover or the contacted portion of the housing, and when the protrusion is inserted into the groove, the inner peripheral side wall of the groove and the inner peripheral side wall of the protrusion are in contact with each other, and a gap is provided between the outer peripheral side wall of the groove and the outer peripheral side wall of the protrusion.

[0040] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

Claims

1. A hydraulic pressure generating device comprising: a housing having a cylinder bore opening in a predetermined opening surface; a piston disposed in the cylinder bore; and a cover attached to the opening surface so as to cover the opening of the cylinder bore, and together with the housing and the piston, partitioning a hydraulic chamber whose volume changes as the piston moves, wherein the cover is bonded to the opening surface of the housing by friction pressure contact.

2. A hydraulic pressure generating device according to claim 1, comprising a rotating member that is rotated when joining the cover and the housing, wherein the cover and the housing are joined by a molten material formed by frictional heat generated when the rotating member rubs against at least one of the cover and the housing, causing the rotating member, the cover, and the housing to melt.

3. The hydraulic pressure generating device according to claim 2, wherein at least one of the cover and the housing has a protrusion that projects outward toward the outside of the hydraulic chamber, and the cover and the housing are joined together by the molten material which is melted by frictional heat generated when the rotating member rubs against the protrusion.

4. The hydraulic pressure generating device according to claim 2 or 3, wherein either the contact portion of the cover that contacts the opening surface of the housing or the contacted portion of the housing that contacts the contact portion of the cover has a groove that fits with the other, the other of the contact portion and the contacted portion has a projection that fits with the groove, and the cover and the housing are joined together by the molten material flowing into the groove.

5. The hydraulic pressure generating device according to claim 1, wherein either the contact portion of the cover that contacts the opening surface of the housing or the contacted portion of the housing that contacts the contact portion of the cover has a groove that fits into the other, the other of the contact portion and the contacted portion has a projection that fits into the groove, and the cover and the housing are joined together by molten material from at least one of the cover and the housing flowing into the groove.

6. The hydraulic pressure generating device according to claim 1, wherein the cover has a hydraulic pressure chamber compartment portion formed in the shape of a bottomed cylindrical part that partitions the hydraulic pressure chamber, and a contact portion that extends from the end of the hydraulic pressure chamber compartment portion and contacts the opening surface of the housing.

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