Second spring seats 62 each have a first support component 63, a second support component 64, and a reinforcing plate 66. The first support component 63 supports the ends of second coil spring 61a in the rotational direction. The second support component 64 extends in the rotational direction from the first support component 63 and supports the end of the second spring 61a in the radial direction. At least part of the reinforcing plate 66 is embedded in at least one of the first and second support components 63 and 64. The reinforcing plate 66 directly or indirectly supports the end of the second spring 61a along with the first and second support components 63 and 64.